t5604: do not expect that HEAD is a valid tagname

09116a1 (refs: loosen over-strict "format" check, 2011-11-16)
introduced a test piece (originally in t5700) that expects to be
able to create a tag named "HEAD" and then a local clone using the
repository as its own reference works correctly.  Later, another
test piece started using this tag starting at acede2e (t5700:
document a failure of alternates to affect fetch, 2012-02-11).

But the breakage 09116a1 fixed was not specific to the tagname
HEAD.  It would have failed exactly the same way if the tag used
were foo instead of HEAD.

Before forbidding "git tag" from creating "refs/tags/HEAD", update
these tests to use 'foo', not 'HEAD', as the name of the test tag.

Signed-off-by: Junio C Hamano <[email protected]>

Author: gitster

t/t5604-clone-reference.sh

@@ -131,7 +131,7 @@ test_expect_success 'cloning with multiple references drops duplicates' '
 
 test_expect_success 'clone with reference from a tagged repository' '
 	(
-		cd A && git tag -a -m tagged HEAD
+		cd A && git tag -a -m tagged foo
 	) &&
 	git clone --reference=A A I
 '
@@ -156,10 +156,10 @@ test_expect_success 'fetch with incomplete alternates' '
 		git remote add J "file://$base_dir/J" &&
 		GIT_TRACE_PACKET=$U.K git fetch J
 	) &&
-	main_object=$(cd A && git for-each-ref --format="%(objectname)" refs/heads/main) &&
+	main_object=$(git -C A rev-parse --verify refs/heads/main) &&
 	test -s "$U.K" &&
 	! grep " want $main_object" "$U.K" &&
-	tag_object=$(cd A && git for-each-ref --format="%(objectname)" refs/tags/HEAD) &&
+	tag_object=$(git -C A rev-parse --verify refs/tags/foo) &&
 	! grep " want $tag_object" "$U.K"
 '