HOME must be set before calling git-init when creating test repositories

Otherwise the created test repositories will be affected by users ~/.gitconfig.
For example, setting core.logAllrefupdates in users config will make all
calls to "git config --unset core.logAllrefupdates" fail which will break
the first test which uses the statement and expects it to succeed.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/test-lib.sh

@@ -1004,14 +1004,14 @@ rm -fr "$test" || {
 	exit 1
 }
 
+HOME="$TRASH_DIRECTORY"
+export HOME
+
 test_create_repo "$test"
 # Use -P to resolve symlinks in our working directory so that the cwd
 # in subprocesses like git equals our $PWD (for pathname comparisons).
 cd -P "$test" || exit 1
 
-HOME=$(pwd)
-export HOME
-
 this_test=${0##*/}
 this_test=${this_test%%-*}
 for skp in $GIT_SKIP_TESTS