Unnecessary usage of java lock in BgpConfigurationManager which leads to thread blocking indefinitely

Right now BgpConfigurationManager uses its intrinsic lock in lot of its methods unnecessarily which can potentially lead to thread blocking (or) even thread deadlock since it has other inner DCN listener classes which add/update/update methods are also synchronized.

For more details look at https://bugs.opendaylight.org/show_bug.cgi?id=8142
For logs: https://drive.google.com/open?id=0B_Rr7XjF0yoHc2EwT1psVGQwRVE