protocol v2 tests: fix cleanup logic in main v2 tests

In e52449b (connect: request remote refs using v2, 2018-03-15)
when these tests were introduced we used the test_when_finished
pattern to clean up, but in most tests added since
ba95710 ({fetch,upload}-pack: support filter in protocol v2,
2018-05-03) we've used "rm -rf" at the start of each test.

Thus we've gone from tests consistently cleaning up after themselves,
to them cleaning up after earlier tests, and some wanting to rely on
previous state, and others not. Let's consistently use the
test_when_finished pattern again. This required merging one test, and
the fixes in the preceding commit.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>

t/t5702-protocol-v2.sh

@@ -409,6 +409,7 @@ test_expect_success 'warn if using server-option with clone with legacy protocol
 '
 
 test_expect_success 'upload-pack respects config using protocol v2' '
+	test_when_finished "rm -rf server client" &&
 	git init server &&
 	write_script server/.git/hook <<-\EOF &&
 		touch hookout
@@ -423,7 +424,6 @@ test_expect_success 'upload-pack respects config using protocol v2' '
 '
 
 test_expect_success 'setup filter tests' '
-	rm -rf server client &&
 	git init server &&
 
 	# 1 commit to create a file, and 1 commit to modify it
@@ -436,6 +436,7 @@ test_expect_success 'setup filter tests' '
 '
 
 test_expect_success 'partial clone' '
+	test_when_finished "rm -rf trace client" &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -c protocol.version=2 \
 		clone --filter=blob:none "file://$(pwd)/server" client &&
 	grep "version 2" trace &&
@@ -449,19 +450,18 @@ test_expect_success 'partial clone' '
 	git -C client fsck
 '
 
-test_expect_success 'dynamically fetch missing object' '
-	rm "$(pwd)/trace" &&
+test_expect_success 'dynamically fetch missing object, does not list refs' '
+	test_when_finished "rm -rf trace client" &&
+	git -c protocol.version=2 \
+		clone --filter=blob:none "file://$(pwd)/server" client &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
 		cat-file -p $(git -C server rev-parse message1:a.txt) &&
-	grep "version 2" trace
-'
-
-test_expect_success 'when dynamically fetching missing object, do not list refs' '
+	grep "version 2" trace &&
 	! grep "git> command=ls-refs" trace
 '
 
 test_expect_success 'partial fetch' '
-	rm -rf client "$(pwd)/trace" &&
+	test_when_finished "rm -rf trace client" &&
 	git init client &&
 	SERVER="file://$(pwd)/server" &&
 
@@ -479,9 +479,9 @@ test_expect_success 'partial fetch' '
 '
 
 test_expect_success 'do not advertise filter if not configured to do so' '
+	test_when_finished "rm -rf trace" &&
 	SERVER="file://$(pwd)/server" &&
 
-	rm "$(pwd)/trace" &&
 	git -C server config uploadpack.allowfilter 1 &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -c protocol.version=2 \
 		ls-remote "$SERVER" &&
@@ -496,7 +496,7 @@ test_expect_success 'do not advertise filter if not configured to do so' '
 '
 
 test_expect_success 'partial clone warns if filter is not advertised' '
-	rm -rf client &&
+	test_when_finished "rm -rf client" &&
 	git -C server config uploadpack.allowfilter 0 &&
 
 	cat >err.expect <<-\EOF &&
@@ -553,7 +553,7 @@ test_expect_success 'default refspec is used to filter ref when fetchcing' '
 '
 
 test_expect_success 'fetch supports various ways of have lines' '
-	rm -rf server client trace &&
+	test_when_finished "rm -rf server client trace" &&
 	git init server &&
 	test_commit -C server dwim &&
 	TREE=$(git -C server rev-parse HEAD^{tree}) &&
@@ -600,9 +600,9 @@ test_expect_success 'fetch supports various ways of have lines' '
 '
 
 test_expect_success 'fetch supports include-tag and tag following' '
-	rm -rf server client trace &&
-	git init server &&
+	test_when_finished "rm -rf server client trace" &&
 
+	git init server &&
 	test_commit -C server to_fetch &&
 	git -C server tag -a annotated_tag -m message &&
 
@@ -618,7 +618,7 @@ test_expect_success 'fetch supports include-tag and tag following' '
 '
 
 test_expect_success 'upload-pack respects client shallows' '
-	rm -rf server client trace &&
+	test_when_finished "rm -rf server client trace" &&
 
 	git init server &&
 	test_commit -C server base &&
@@ -640,7 +640,7 @@ test_expect_success 'upload-pack respects client shallows' '
 '
 
 test_expect_success 'ensure that multiple fetches in same process from a shallow repo works' '
-	rm -rf server client trace &&
+	test_when_finished "rm -rf server client trace" &&
 
 	test_create_repo server &&
 	test_commit -C server one &&
@@ -658,8 +658,7 @@ test_expect_success 'ensure that multiple fetches in same process from a shallow
 '
 
 test_expect_success 'deepen-relative' '
-	test_when_finished "rm -rf server client" &&
-	rm -rf server client trace &&
+	test_when_finished "rm -rf server client trace" &&
 
 	test_create_repo server &&
 	test_commit -C server one &&
@@ -1255,6 +1254,7 @@ test_expect_success 'packfile-uri with transfer.fsckobjects fails when .gitmodul
 	P="$HTTPD_DOCUMENT_ROOT_PATH/http_parent" &&
 	rm -rf "$P" http_child err &&
 
+	test_when_finished "rm -rf \"$P\"" &&
 	git init "$P" &&
 	git -C "$P" config "uploadpack.allowsidebandall" "true" &&
 
@@ -1282,6 +1282,7 @@ test_expect_success 'packfile-uri with transfer.fsckobjects fails when .gitmodul
 '
 
 test_expect_success 'http:// --negotiate-only' '
+	rm -rf server client &&
 	SERVER="$HTTPD_DOCUMENT_ROOT_PATH/server" &&
 	URI="$HTTPD_URL/smart/server" &&