windows7-64-py2.7-msi fails if warnings are written to stdout

[Jean-Paul Calderone]

windows7-64-py2.7-msi discovers the Twisted version by importing Twisted. The version is required to build an MSI. The discovery code fails if anything other than the version is written out when importing twisted to learn the version, though, as seen on a recent build:

http://buildbot.twistedmatrix.com/builders/windows7-64-py2.7-msi/builds/1123

This doesn't show up in trunk due to luck, thanks to nothing in twisted/__init__.py currently triggering any warnings. The above build is from a branch which adds a zope.interface import to twisted/__init__.py.

[Tom Prince (tom.prince)]

This requires adding an option to the SetProperty to ignore stderr.

[Glyph Lefkowitz (glyph)]

This is blocking a Twisted issue, <http://twistedmatrix.com/trac/ticket/5935#comment:10>, so I would say it's high priority.