Hyperv mech_driver has been moved out of neutron core code, and it
became a stand alone package. Current network cookbook did not
install the hyperv mech_driver, so add the logic in hyperv recipe
to intall the hyperv mech_driver when the hyperv is configured in
mechanism_drivers of environment.
Currently there is no package for hyperv mech_driver in all linux
distribution, as the hyperv mech_driver code has been moved out of
neutron code. So here names the package networking-hyperv by
default, overwrite the package name when other users generate the
packages themselves.
Change-Id: I0d27f41e2dc068fc0dd2a67fef5999a006f685dd
Closes-Bug: 1475151
08bd03d011