Laravel 5.6 updates

Travis config update

Removed HHVM script as Laravel no longer support HHVM after releasing 5.3

vendor/symfony/console/Tests/Command/LockableTraitTest.php

@@ -41,7 +41,7 @@ class LockableTraitTest extends TestCase
     {
         $command = new \FooLockCommand();
 
-        if (SemaphoreStore::isSupported(false)) {
+        if (SemaphoreStore::isSupported()) {
             $store = new SemaphoreStore();
         } else {
             $store = new FlockStore();