1. Protect DescriptorPool::BuildFile in ProtobufReader using mutex
2. Protect boost::uuids::random_generator in DbHandler using mutex
3. Copy over the errors from SocketStats to SocketIOStats

Added tests for the following in DbHandler:
1. Tests that show boost::uuids::random_generator is not thread-safe.
   This test is disabled since it fails as expected with duplicate
   uuids being returned.
2. Test that shows creating a boost::uuids::random_generator on stack
   is an order of magnitude expensive than not doing so or
   multi-threaded mutex lock based approach.

Change-Id: I22326c132ff733005312722461a0c5e831fbb964
Addressing review comments from ipv6 commits

Change-Id: Ie3148b22d4b0424cc9e6cd7e11773d952f97b338
Fix memory leak in DB tests

Make sure DB_RunNotify_Yield deletes entries that it added.

Change-Id: Ibc019addea7f5fe545fd04fb799d04947adbe7b7
Promote bgp_stress_test from flaky to non-flaky

Change-Id: I9a9c643cf0ca6d84ffdb0e6b6e0f05777bf7c2de
send RA to all nodes address

Change-Id: Iea84b102d2c924d30a4c5eebb00da352dd578049
Merge "Addressing review comments from ipv6 commits"
Merge "send RA to all nodes address"
Implement DBTable API to notify all entries

Change-Id: I6a2646167cc564a7c228c86f94d33bef7134177d
Merge "Promote bgp_stress_test from flaky to non-flaky"
Merge "Implement DBTable API to notify all entries"
Merge "1. Protect DescriptorPool::BuildFile in ProtobufReader using mutex 2. Protect boost::uuids::random_generator in DbHandler using mutex 3. Copy over the errors from SocketStats to SocketIOStats"
Merge "Fix memory leak in DB tests"
Implement support for transit network

Change-Id: I9c81ba61a3bf0e8db04577b09ee26aa5aa60ad4d