Remove no longer needed r/w lock interface base class

This interface/class was put in place when this code was being
more actively developed to ensure that both the dummy and the
actual class had the same methods, since these two classes
have apis that are now stable we no longer need to have a base
class to enforce the implemented api that itself provides no
added functionality.

Change-Id: Ida4f86b308941ff708db5395a1d266c0c4b75815
Merge "Remove no longer needed r/w lock interface base class"