Patch in: 69c88b64701caaac414bbc753061dfd86094c518 missed commit

commit 69c88b64701caaac414bbc753061dfd86094c518
Author: Megh Bhatt <meghb@juniper.net>
Date:   Thu Dec 19 15:46:39 2013 -0800

    1. Fix potential memory corruption caused by accessing and modifying
       last_event in SandeshStateMachine and SandeshClientSM from
       concurrent threads by using the state machine mutex.
    2. Consolidate state machine event statistics into a common
       structure - SandeshEventStatistics - sandesh_statistics.h
       and let both SandeshStateMachine and SandeshClientSM use it.