CFY-766 add method for waiting on an execution
CFY-766 add method for waiting on an execution

cloudify-cosmo/cloudify-system-tests,isaac-s/cloudify-system-tests,codilime/cloudify-system-tests,codilime/cloudify-system-tests,isaac-s/cloudify-system-tests,isaac-s/cloudify-system-tests,codilime/cloudify-system-tests,cloudify-cosmo/cloudify-system-tests