Increased the timout to 60s while waiting for mesos cluster to start …

…properly

src/main/java/org/apache/mesos/mini/util/MesosClusterStateResponse.java

@@ -41,7 +41,7 @@ public Boolean call() throws Exception {
     public void waitFor() {
 
         await()
-                .atMost(20, TimeUnit.SECONDS)
+                .atMost(60, TimeUnit.SECONDS)
                 .pollInterval(1, TimeUnit.SECONDS)
                 .until(this, is(true));