tests: Skip tests in a way that makes sense under TAP

SKIP messages are now part of the TAP plan. A TAP harness now knows
why a particular test was skipped and can report that information. The
non-TAP harness built into Git's test-lib did nothing special with
these messages, and is unaffected by these changes.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/lib-git-svn.sh b/t/lib-git-svn.sh
index 0f7f35c..344785d 100644
--- a/t/lib-git-svn.sh
+++ b/t/lib-git-svn.sh
@@ -5,11 +5,11 @@
 
 if test -n "$NO_SVN_TESTS"
 then
-	say 'skipping git svn tests, NO_SVN_TESTS defined'
+	skip_all='skipping git svn tests, NO_SVN_TESTS defined'
 	test_done
 fi
 if ! test_have_prereq PERL; then
-	say 'skipping git svn tests, perl not available'
+	skip_all='skipping git svn tests, perl not available'
 	test_done
 fi