filter-branch.sh: remove temporary directory on failure

One of the first things filter-branch does is to create a temporary
directory. This directory is eventually removed by the script during
normal operation, but is not removed if the script encounters an error.

Set a trap to remove it when the script terminates for any reason.

Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-filter-branch.sh

@@ -189,6 +189,9 @@ cd "$tempdir/t" &&
 workdir="$(pwd)" ||
 die ""
 
+# Remove tempdir on exit
+trap 'cd ../..; rm -rf "$tempdir"' 0
+
 # Make sure refs/original is empty
 git for-each-ref > "$tempdir"/backup-refs
 while read sha1 type name
@@ -406,6 +409,8 @@ fi
 cd ../..
 rm -rf "$tempdir"
 
+trap - 0
+
 unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE
 test -z "$ORIG_GIT_DIR" || GIT_DIR="$ORIG_GIT_DIR" && export GIT_DIR
 test -z "$ORIG_GIT_WORK_TREE" || GIT_WORK_TREE="$ORIG_GIT_WORK_TREE" &&