subdirectory tests: code cleanup, uncomment test

Back when these tests were written, we wanted to make sure that Git
notices it is in a bare repository and "git show -s HEAD" would
refrain from complaining that HEAD might mean a file it sees in its
current working directory (because it does not).  But the version of
Git back then didn't behave well, without (doubly) being told that
it is inside a bare repository by exporting "GIT_DIR=.".  The form
of the test we originally wanted to have was left commented out as
a reminder.

Nowadays the test as originally intended works, so add it to the
test suite.  We'll keep the old test that explicitly sets GIT_DIR=.
to make sure that use case will not regress.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1020-subdirectory.sh

@@ -162,16 +162,20 @@ test_expect_success 'no file/rev ambiguity check inside .git' '
 	)
 '
 
-test_expect_success 'no file/rev ambiguity check inside a bare repo' '
+test_expect_success 'no file/rev ambiguity check inside a bare repo (explicit GIT_DIR)' '
+	test_when_finished "rm -fr foo.git" &&
 	git clone -s --bare .git foo.git &&
 	(
 		cd foo.git &&
+		# older Git needed help by exporting GIT_DIR=.
+		# to realize that it is inside a bare repository.
+		# We keep this test around for regression testing.
 		GIT_DIR=. git show -s HEAD
 	)
 '
 
-# This still does not work as it should...
-: test_expect_success 'no file/rev ambiguity check inside a bare repo' '
+test_expect_success 'no file/rev ambiguity check inside a bare repo' '
+	test_when_finished "rm -fr foo.git" &&
 	git clone -s --bare .git foo.git &&
 	(
 		cd foo.git &&
@@ -180,7 +184,6 @@ test_expect_success 'no file/rev ambiguity check inside a bare repo' '
 '
 
 test_expect_success SYMLINKS 'detection should not be fooled by a symlink' '
-	rm -fr foo.git &&
 	git clone -s .git another &&
 	ln -s another yetanother &&
 	(