Refactor of PDP Agent code.
Moved shared functionality up the the super COPSPdpAgent. Clarified purpose of the class by removing the extension of the Thread class as the agent is responsible for creating the persistent connection via the COPSPdpConnection class not itself. It appears that the class was originally meant handle COPS messages at one point but the run() method or extension of Thread was never removed after adding the connection object.
Change-Id: I5fd9b5dd914cf902c8726821253491f316e7d93f
Signed-off-by: Steven Pisarski <s.pisarski@cablelabs.com>