server: correct comment typo on port being after ':'

We use commas in fio, since that works equally well on IPv4
and IPv6.

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/server.c b/server.c
index 2f12162..32d6914 100644
--- a/server.c
+++ b/server.c
@@ -1485,7 +1485,7 @@
 	}
 
 	/*
-	 * If no port seen yet, check if there's a last ':' at the end
+	 * If no port seen yet, check if there's a last ',' at the end
 	 */
 	if (!lport) {
 		portp = strchr(host, ',');