buildbot/buildbot — pull request #573 by jhnwsk (2012-11-14 17:00:55+00:00)
Title: fix steps.master env sub failing when env[key] is list

I was following the [documentation](http://buildbot.net/buildbot/docs/0.8.7/manual/cfg-buildsteps.html#step-MasterShellCommand) trying to make the buildbot install my app into a different virtualenv. I found that buildbot complains if a list is among the values of the env dict.

Not sure about the ```:``` separator on other platforms than linux.