This brings multiple commits from Atul for subnet allocation pools to mainline from R1.06 branch.

Change-Id: Ibdd0833dcfd63245ce6df31a66511aafdd427b39
Commit#1
Bug#2989 - agent cored at std::string::assign(std::string const&)

Fix:
For every XMPP channel in agent create a unicast sequence number.
This number will be carried with DB request. In case BGP peer has
changed in channel then the number is incremented and any request not belonging
to
the new sequence number will be ignored.
The information is being sent using data part of request.

Commit#2
Bug 3068 - Security group id zero, even the agent ifmap shows a value '7'.
Skip config with sg id as 0.

Commit#3
Add headless mode config in contrail-vrouter-agent.conf.
Also make the param name consistent to
headless_mode in argument and config.

Change-Id: I55af7d6b1160406c8022bdade0091e9cf12d7563
Merge "Commit#1 Bug#2989 - agent cored at std::string::assign(std::string const&)"
Enable test cases:
test_mirror
test_nh
test_multicast
test_tunnel_encap

Change-Id: Ia6ac9b471e9293b7a3bc2e94b84b11d6cac19bdb
Flow key changes

Change-Id: Ied672d0fcd7d3e56fb4ff08e67780aa8dc43e107
Merge "Enable test cases: test_mirror test_nh test_multicast test_tunnel_encap"
Merge "Flow key changes"
Vmware Agent changes

Change-Id: Ic5318020dedc6a7a40312a3770c002eace661774
Checks for subnet update were not taking into account that some fields may not be specified. In that case, we should assume default values

Change-Id: Id29229c12f6c89e740584cbadeb6939b7cee3679
Neutron plugin thinning backend code in API server

Change-Id: I33c85663777b2e72f5961ca5ef4a78396626b47c
Merge "Checks for subnet update were not taking into account that some fields may not be specified. In that case, we should assume default values"
Merge "Vmware Agent changes"
Fixing the Agent unit test compilation issues

Change-Id: I9ecce71242829d61b1f07e85fe571211b648e53e
Ignore link update for SG node where sg id is invalid

Change-Id: I7a2ec08a076592f06825d477d1320cec14877671
Bug 1326969: fix issues in get_ports and get_floatingips

Change-Id: I7b4dbb267046fb27f92188d493bc83357c10aa07
setting gw to first+1 if gw_ip is not given in subnet_create, fixed dns_nameserver display issue in subnet_vnc_to_neutron()

Change-Id: Icb4bc30ebdbc548a4f6e7e8714308b60e9f95aaf
Prevent overwrite of subnet object in IPAM

Change-Id: I13c11f9e3187d882823932d3e07a6a93d4cfd417
Merge "Prevent overwrite of subnet object in IPAM"
Merge "Bug 1326969: fix issues in get_ports and get_floatingips"
Fix issues in add/delete router interface.

Change-Id: Ie1f1a618824c87a2ba7787fdd3d5e7241bb870ff