add cli.has_manage option

this indicates if tempest is being run in an environment where the
*-manage commands could be run. This will not be all environments,
but if you happen to be running tempest on your management node
it is nice to be able to test these things.

Change-Id: I5fcabc19afc90950ee214343789dcfc13fc370a1
Closes-Bug: #1282178
Merge "add cli.has_manage option"