Repeatedly add log_filters,log_outputs to libvirtd.conf when restart

Change-Id: I14f07f3164f9201305ed1e94e9277a5a5792e850
Closes-bug: 1273058
allow for upgrade of the precise kernel

we are getting kernel crashes in the OpenStack gate, to test
getting around this we'd like devstack to be able to upgrade
the precise kernel to the latest lts backported kernel.

default to off

Change-Id: I5d47aa8d15b1b1c0386a13b65022f6b8108c5c49
Convert trove to plugin

Also adds an is_trove_enabled() function to match
https://review.openstack.org/69497 changes for is_service_enabled().

Change-Id: Ic0408ff6d9816aec8a3506931470470342a5dcd7
Merge "Repeatedly add log_filters,log_outputs to libvirtd.conf when restart"
Merge "Convert trove to plugin"
Merge "allow for upgrade of the precise kernel"