Install necessary packages for ML2

In case of multihost instalations mechanism packages might not be installed
(agent might be installed on different host). In this case we have to install
appropriate plugins.

Change-Id: I62aab85378c6f3d6bb4bd53e3ac49c64106d6e3a
(cherry picked from commit 3e3473c1b80c936eaee44200e46e5f3d4bf96211)
Merge "Install necessary packages for ML2" into havana