Allows accepting modified (UUID) redhat-manifest

Add a task to setup a fake manifest certificate and restart tomcat.
Fix call to setup_fake_manifest_certificate task

Call setup_fake_manifest_certificate task using execute and passing the
host argument to run on the provisioned machine and not in the
provisioning server.
Add RHEL7 support for upstream installation
Try to subscribe to a pool 3 times

Subscribing to a pool sometimes fails due to a race condition.  With
this change, the process happens 3 times before failing. And continue
normally as soon as the command works.