Remove install-plugin from acceptance test script
Remove install-plugin from acceptance test script

The plugin is already included in our container image. The run script
tries to install is from the package and fails. We work around that by
deleting the line from the script.

https://github.com/cloudfoundry/cf-release/issues/1188 has been raised.
This commit should be reverted once the issue is solved.

alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf