This change will allow glance services to run on Windows, using
eventlet wsgi for API services.
This change will:
* avoid monkey patching the os module on Windows (which causes Popen
to fail)
* avoiding unavailable signals
* avoid renaming in-use files or leaking handles
* update the check that ensures that just one scrubber process may
run at a time. We can't rely on process names as there might be
wrapper processes that have similar names (no she-bangs on Windows,
so the scripts are called a bit differently). We'll use a global
named mutex instead.
A subsequent change will leverage Windows job objects as a
replacement for process groups, also avoiding forking when spawning
workers.
At the moment, some Glance tests cannot run on Windows, which is
also covered by subsequent patches.
DocImpact
blueprint windows-support
Change-Id: I3bca69638685ceb11a1a316511ad9a298c630ad5
5759ec0b1c