Ensure consistency with return code checking, PEP-20 updates
Ensure consistency with return code checking, PEP-20 updates

Previously we were ignoring the return code from libvirt calls and
simply returning True without actually signalling if the call succeeded.
There were a couple places in the code that the libvirt return was
checked to '== 0' but now all calls that return a boolean status use
this same logic.

There were a few places where we were catching all exceptions to
determine if we succeeded or not. There's no reason to catch all
exceptions as it may mask a deeper issue. (PEP-20)

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt