[Merge] lp:~jamesodhunt/upstart/setenv+getenv into lp:upstart

[Stéphane Graber]

The original planned use for this feature was specifically for a single job to be able to affect the environment of all future jobs, so we'll definitely need to retain that feature, but I'm happy with a --global flag.
-- 
https://code.launchpad.net/~jamesodhunt/upstart/setenv+getenv/+merge/142939
Your team Upstart Reviewers is requested to review the proposed merge of lp:~jamesodhunt/upstart/setenv+getenv into lp:upstart.