chore(tests): fix socket error in karma

related with karma-runner/karma#1782

Author: Kamil Kisiela

package.json

@@ -79,7 +79,7 @@
     "isparta": "3.1.0",
     "isparta-loader": "1.0.0",
     "istanbul": "0.4.0",
-    "karma": "0.13.14",
+    "karma": "0.13.19",
     "karma-chai": "0.1.0",
     "karma-chrome-launcher": "0.2.1",
     "karma-coverage": "0.5.3",