Clean up Cisco plugin config parameters

Fixes: bug 1201537

Change-Id: Ibb5a9a12ee451c317ae747924b336ffa044a20b1
LBaaS: add delete_health_monitor() to driver API

Currently there is create_health_monitor() in the driver API so
a driver may create an object on device but there is no delete_health_monitor()
and monitor objects will remain on device forever.
Driver should at least call plugin to delete a db object.

Fixes bug 1198996

Change-Id: Idcdaea0636e01381064983d8de5bfe3936357fb9
Merge "LBaaS: add delete_health_monitor() to driver API"
Merge "Clean up Cisco plugin config parameters"