gpg-interface/gpgsm: fix for v2.3

Checking if signing was successful will now accept '[GNUPG]:
SIG_CREATED' on the beginning of the first or any subsequent line. Not
just explictly the second one anymore.

Gpgsm v2.3 changed its output when listing keys from `fingerprint` to
`sha1/2 fpr`. This leads to the gpgsm tests silently not being executed
because of a failed prerequisite.
Switch to gpg's `--with-colons` output format when evaluating test
prerequisites to make parsing more robust. This also allows us to
combine the existing grep/cut/tr/echo pipe for writing the trustlist.txt
into a single awk expression.

Adjust error message checking in test for v2.3 specific output changes.

Helped-By: Junio C Hamano <gitster@pobox.com>
Helped-By: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/lib-gpg.sh

@@ -72,12 +72,10 @@ test_lazy_prereq GPGSM '
 		--passphrase-fd 0 --pinentry-mode loopback \
 		--import "$TEST_DIRECTORY"/lib-gpg/gpgsm_cert.p12 &&
 
-	gpgsm --homedir "${GNUPGHOME}" -K |
-	grep fingerprint: |
-	cut -d" " -f4 |
-	tr -d "\\n" >"${GNUPGHOME}/trustlist.txt" &&
+	gpgsm --homedir "${GNUPGHOME}" -K --with-colons |
+	awk -F ":" "/^fpr:/ {printf \"%s S relax\\n\", \$10}" \
+		>"${GNUPGHOME}/trustlist.txt" &&
 
-	echo " S relax" >>"${GNUPGHOME}/trustlist.txt" &&
 	echo hello | gpgsm --homedir "${GNUPGHOME}" >/dev/null \
 	       -u committer@example.com -o /dev/null --sign -
 '