(PUP-3069) Halt compile if environment has manifest conflict

Henrik brought up that with the new restrict_environment_manifest
setting set true, authors of modules in a particular environment
may be surprised by a manifest they have specified in their
environment.conf not being pulled in, leading to bad behavior when a
catalog is executed. Although this is logged on the master, compilation
delivery and catalog execution is not prevented.

This commit will raise an exception on the master prior to catalog
compilation if it detect's a conflict between manifest settings in the
requested environment.