dns: fix cares memory leak

Author: theanarkh

src/cares_wrap.cc

@@ -1473,11 +1473,16 @@ void AfterGetAddrInfo(uv_getaddrinfo_t* req, int status, struct addrinfo* res) {
       return Just(true);
     };
 
-    if (add(true, verbatim).IsNothing())
+    if (add(true, verbatim).IsNothing()) {
+      uv_freeaddrinfo(res);
       return;
+    }
+
     if (verbatim == false) {
-      if (add(false, true).IsNothing())
+      if (add(false, true).IsNothing()) {
+        uv_freeaddrinfo(res);
         return;
+      }
     }
 
     // No responses were found to return