t5305: drop "dry-run" of unpack-objects

For each test we do a dry-run of unpack-objects, followed by
a real run, followed by confirming that it contained the
objects we expected. The dry-run is telling us nothing, as
any errors it encounters would be found in the real run.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5305-include-tag.sh

@@ -37,7 +37,6 @@ test_expect_success 'unpack objects' '
 		GIT_DIR=clone.git &&
 		export GIT_DIR &&
 		git init &&
-		git unpack-objects -n <test-1-${packname_1}.pack &&
 		git unpack-objects <test-1-${packname_1}.pack
 	)
 '
@@ -64,7 +63,6 @@ test_expect_success 'unpack objects' '
 		GIT_DIR=clone.git &&
 		export GIT_DIR &&
 		git init &&
-		git unpack-objects -n <test-2-${packname_1}.pack &&
 		git unpack-objects <test-2-${packname_1}.pack
 	)
 '