Update log control flag by using Log.isLoggable

The log is completely disabled in the TcpSocketTracker. It's
impossible to debug without building and flashing a new module.
Change the bit to refer to Log.isLoggable so that the log could
be controlled via property in the runtime. Also, update some
logs to help debugging.

Test: m ; observe log via changing the log prop
Change-Id: I7dd26cd3d14a3f2b50e51fd99fce4a4be7183a8c