Clean up zones root path

Clean up zones root path

[Feature]       Clean up zones root path (according to cleanUpZonesPath flag)
[Cause]         N/A
[Solution]      Added cleanUpZonesPath to daemon.conf which tells whether
                to remove unknown files from the zonesPath;
                Added (vsm_)clean_up_zones_root to cli and client
[Verification]  Build, install, create files in zonesPath,
                run vasum-server with different flag value, check if
                zonesPath is as it should; execute command

Change-Id: I64a1656ef05ccd5fd7e83a48cd50234e2e6bd4b4