Fix a couple uninitialized variable warnings in the release build.

Reviewed-by: Eliseo Martínez <eliseomarmol@gmail.com>
Reviewed-by: Marco Hinz <mh.codebro@gmail.com>
Reviewed-by: Björn Linse <bjorn.linse@gmail.com>

src/nvim/msgpack_rpc/server.c

@@ -238,7 +238,7 @@ void server_stop(char *endpoint)
     }
   }
 
-  if (i == servers.ga_len) {
+  if (i >= servers.ga_len) {
     ELOG("Not listening on %s", addr);
     return;
   }