MFportsnap r264740: Use case insensitive match when parsing host(1) output.

Some DNS caches turn "FreeBSD.org" into "freebsd.org", which was causing
the printed SRV records to not match our regex.

PR:		170503
MFC after:	2 weeks

usr.sbin/freebsd-update/freebsd-update.sh

@@ -953,7 +953,7 @@ fetch_pick_server_init () {
 # "$name server selection ..."; we allow either format.
 	MLIST="_http._tcp.${SERVERNAME}"
 	host -t srv "${MLIST}" |
-	    sed -nE "s/${MLIST} (has SRV record|server selection) //p" |
+	    sed -nE "s/${MLIST} (has SRV record|server selection) //Ip" |
 	    cut -f 1,2,4 -d ' ' |
 	    sed -e 's/\.$//' |
 	    sort > serverlist_full