Restore the automatic enabling of plugins loaded from an environment's `plugins` dir, behavior which was broken by r3771. Fixes #3288.
Restore the automatic enabling of plugins loaded from an environment's
`plugins` dir, behavior which was broken by r3771. Fixes #3288.


git-svn-id: f68c6b3b1dcd5d00a2560c384475aaef3bc99487@3434 af82e41b-90c4-0310-8c96-b1721e28e2e2

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