Fixed dhcp & gateway ip conflict in PLUMgrid plugin

   * Adjust dhcp IP if conflicts with gateway IP
   * Added unit test case

Closes-Bug:1333442
Change-Id: Iaa4e63faf28b783e6b5dbc50035ca50ccde9951a
remove unsupported middleware

the audit and notifier middleware from oslo-incubator are not
compatible with oslo.messaging. remove these middleware.

Change-Id: I456c2aa5f24ef977949f589f72d521514d5e97e4
Merge "remove unsupported middleware"
Merge "Fixed dhcp & gateway ip conflict in PLUMgrid plugin"