Removed env variable from examples test.

Will use the value from env_vars.sh.

Author: freskoulix

bin/test_examples.sh

@@ -2,7 +2,6 @@
 
 source ./env_vars.sh
 export CAPABILITIES='capabilities_firefox.yaml'
-export CODEBENDER_SELENIUM_HUB_URL="http://127.0.0.1:4444/wd/hub"
 cd ..
 time tox tests/libraries -- --url=https://codebender.cc --source=codebender_cc -F
 RETVAL=$?