t/t1304: make a second colon optional in the mask ACL check

Solaris only uses one colon in the listing of the ACL mask, Linux uses two,
so substitute egrep for grep and make the second colon optional.

The -q option for Solaris 7's /usr/xpg4/bin/egrep does not appear to be
implemented, so redirect output to /dev/null.

Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1304-default-acl.sh

@@ -25,7 +25,7 @@ check_perms_and_acl () {
 	getfacl "$1" > actual &&
 	grep -q "user:root:rwx" actual &&
 	grep -q "user:${LOGNAME}:rwx" actual &&
-	grep -q "mask::r--" actual &&
+	egrep "mask::?r--" actual > /dev/null 2>&1 &&
 	grep -q "group::---" actual || false
 }