PAP erroneously undeploying policies

PAP erroneously undeploying policies

The problem appears to be a multi-threading type of issue:
- PAP sends request to XACML
- JMeter pushes the next deployment request into PAP
- PAP receives response from XACML
  - based on request ID, the response is routed to the handler,
    but blocks while PAP processes the deployment request
- PAP replaces old list of policies with new, and changes the
  request ID
- PAP responds to JMeter
- PAP handles XACML response, even though it's request ID no
  longer matches

Modified PAP to no longer replace any messages that are at the
head of the queue.
Fixed the license.

Issue-ID: POLICY-2527
Change-Id: I43218a7d0591649d761e17282189e51d5dbd26ed
Signed-off-by: Jim Hahn <jrh3@att.com>