[create-project] If process terminated with SIGINT then 130 IMO will be returned. Remove unused variable

src/Composer/Command/CreateProjectCommand.php

@@ -293,11 +293,10 @@ EOT
         // handler Ctrl+C for unix-like systems
         if (function_exists('pcntl_signal')) {
             declare(ticks = 100);
-            $isPcntlHandler = true;
             pcntl_signal(SIGINT, function() use ($directory) {
                 $fs = new Filesystem();
                 $fs->removeDirectory($directory);
-                exit();
+                exit(130);
             });
         }