env: Fixed `Environment` so that `IEnvironmentSetupParticipant.environment_created()` is actually called on creation.
env: Fixed `Environment` so that `IEnvironmentSetupParticipant.environment_created()` is actually called on creation.

Patch by jomae. Part of #9416.


git-svn-id: f68c6b3b1dcd5d00a2560c384475aaef3bc99487@9847 af82e41b-90c4-0310-8c96-b1721e28e2e2

moreati/trac-gitsvn,moreati/trac-gitsvn,moreati/trac-gitsvn,dafrito/trac-mirror,dafrito/trac-mirror,exocad/exotrac,dafrito/trac-mirror,exocad/exotrac,exocad/exotrac,dafrito/trac-mirror,moreati/trac-gitsvn,exocad/exotrac