Patch in: a55da8baa9ea42df7234a72daf1064c9547f1779

commit a55da8baa9ea42df7234a72daf1064c9547f1779
Author: Megh Bhatt <meghb@juniper.net>
Date:   Thu Dec 12 16:40:50 2013 -0800

    1. Added high and low water mark to WorkQueue
    2. Added bounded WorkQueue implementation
    3. Added unit test for work queue
    4. Enabled unit test execution in src/base
    5. Added capability to drop systemlog, objectlog, and flow
       Sandesh messages based on the SandeshLevel of the
       message and using the water mark facility of the
       SandeshQueue
    6. Distinguish between flow setup/teardown and flow sample
       messages sent from vrouter so that we can drop them
       based on water marks
    7. Added introspect to set the water marks for sandesh send queue
       and database queue
    8. Added water marks for database queue in vizd and drop systemlog,
       objectlog, and flow sandesh messages based on level and water
       mark.