Merge "Reuse caller's session in ML2 DB methods"

diff --cc neutron/db/securitygroups_rpc_base.py
Simple merge

diff --cc neutron/plugins/ml2/plugin.py
Simple merge

diff --cc neutron/plugins/ml2/rpc.py
Simple merge

diff --cc neutron/tests/unit/agent/test_securitygroups_rpc.py
Simple merge

diff --cc neutron/tests/unit/plugins/ml2/test_plugin.py
Simple merge

diff --cc neutron/tests/unit/plugins/ml2/test_rpc.py
Simple merge