t7030: stop using invalid tag name

We intentionally invalidate the signature of a tag by switching its tag
name from "seventh" to "7th forged". However, the latter is not a valid
tag name because it contains a space. This doesn't currently affect the
test, but we're better off using something syntactically valid. That
reduces the number of possible failure modes in the test, and
future-proofs us if git hash-object gets more picky about its input.

The t7031 script, which was mostly copied from t7030, has the same
problem, so we'll fix it, too.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t7030-verify-tag.sh b/t/t7030-verify-tag.sh
index 10faa64..6f526c3 100755
--- a/t/t7030-verify-tag.sh
+++ b/t/t7030-verify-tag.sh
@@ -115,7 +115,7 @@
 
 test_expect_success GPG 'detect fudged signature' '
 	git cat-file tag seventh-signed >raw &&
-	sed -e "/^tag / s/seventh/7th forged/" raw >forged1 &&
+	sed -e "/^tag / s/seventh/7th-forged/" raw >forged1 &&
 	git hash-object -w -t tag forged1 >forged1.tag &&
 	test_must_fail git verify-tag $(cat forged1.tag) 2>actual1 &&
 	grep "BAD signature from" actual1 &&