MINOR: cli: ability to change a server's port

Enrichment of the 'set server <b>/<s> addr' cli directive to allow changing
now a server's port.
The new syntax looks like:
  set server <b>/<s> addr [port <port>]
diff --git a/src/dumpstats.c b/src/dumpstats.c
index fa646c0..0a047b8 100644
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -1800,7 +1800,20 @@
 				appctx->st0 = STAT_CLI_PRINT;
 			}
 			else if (strcmp(args[3], "addr") == 0) {
-				warning = server_parse_addr_change_request(sv, args[4], "stats command");
+				char *addr = NULL;
+				char *port = NULL;
+				if (strlen(args[4]) == 0) {
+					appctx->ctx.cli.msg = "set server <b>/<s> requires an <addr> .\n";
+					appctx->st0 = STAT_CLI_PRINT;
+					return 1;
+				}
+				else {
+					addr = args[4];
+				}
+				if (strcmp(args[5], "port") == 0) {
+					port = args[6];
+				}
+				warning = update_server_addr_port(sv, addr, port, "stats socket command");
 				if (warning) {
 					appctx->ctx.cli.msg = warning;
 					appctx->st0 = STAT_CLI_PRINT;