url.c: fix SIGSEGV

lib/url.c

@@ -3858,6 +3858,8 @@ static CURLcode parseurlandfillconn(struct SessionHandle *data,
   else {
     /* sanitise paths and remove ../ and ./ sequences according to RFC3986 */
     char *newp = Curl_dedotdotify(path);
+    if(!newp)
+      return CURLE_OUT_OF_MEMORY;
 
     if(strcmp(newp, path)) {
       rebuild_url = TRUE;