t1500: more 'git rev-parse --git-dir' tests

Extend t1500 with tests of 'git rev-parse --git-dir' when invoked from
other directories of the repository or the work tree.
Signed-off-by: NSZEDER Gábor <szeder@ira.uka.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/t1500-rev-parse.sh

@@ -37,17 +37,17 @@ test_rev_parse() {
 
 ROOT=$(pwd)
 
-test_rev_parse toplevel false false true ''
+test_rev_parse toplevel false false true '' .git
 
 cd .git || exit 1
-test_rev_parse .git/ false true false ''
+test_rev_parse .git/ false true false '' .
 cd objects || exit 1
 test_rev_parse .git/objects/ false true false '' "$ROOT/.git"
 cd ../.. || exit 1
 
 mkdir -p sub/dir || exit 1
 cd sub/dir || exit 1
-test_rev_parse subdirectory false false true sub/dir/
+test_rev_parse subdirectory false false true sub/dir/ "$ROOT/.git"
 cd ../.. || exit 1
 
 git config core.bare true