This prevents client libvirt version 0.8.8 to segfault when reseting libvirt
event handlers.

sending events on removed domains or sending removed event too late.

Type is the same as returned by libvirt (for now).
One of dir, fs, netfs, logical, disk, iscsi, mpath, rbd.

Harmless renaming.

Libvirt raises an exception saying "domain not runnning" when trying to destroy
a VM that is in fact running. So we try to figure out if this is this kind of
exception and we ignore it in this case.

Only log error in case of error.

Support for registering/unregistering sub object to the cc-server.
Support for tag lifecycle handling (libev), was previously managed by plugins.

Try to connect to libvirt while no exception is thrown.

Clean global variable for libvirt connection.