bin: add --set-maintenance to hosted-engine

Add support for --set-maintenance=local|global|none
to hosted-engine command.

Change-Id: If2e07a4ac57268a18523a3119d60b10021f36cfa
Bug-Url: https://bugzilla.redhat.com/1020858
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>