wait more for Android testing

https://travis-ci.org/msgpack/msgpack-javascript/jobs/539247978

Author: gfx

.travis.yml

@@ -42,7 +42,7 @@ script: |
   if [ "${BROWSER}" = "" ]
     then npm run test:cover
   else
-    travis_wait 300 npm run test:browser -- --browsers "$BROWSER"
+    travis_wait 600 npm run test:browser -- --browsers "$BROWSER"
   fi
 after_success: |
   if [ "${BROWSER}" = "" ]