OVSDB Server connection initiation to be configurable

[Sukhdev Kapur]

This bug is actually a feature request.

In current implementation, L2 Gateway Agent initiates a connection to the OVSDB Server.
A configurable option is needed so that the connection can be initiated in reverse order - i.e. OVSDB sever should be able to initiate the connection to L2GW agent. A configuration knob can be added to the .ini file which specifies that the operator wants OVSDB server to initiate the connection - in this case, the address to the OVSDB server will not be specified in the .ini file.

I spoke with Maruti and Selvakumar about the details of the implementation of this in Vancouver.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/208524
Committed: https://git.openstack.org/cgit/openstack/networking-l2gw/commit/?id=9b6ee5df9af1c9c68732e4df1ed74b05d51e66b6
Submitter: Jenkins
Branch: master

commit 9b6ee5df9af1c9c68732e4df1ed74b05d51e66b6
Author: vikas <email address hidden>
Date: Mon Aug 3 07:54:06 2015 -0700

    ovsdb server connection initiation implementation

    ovsdb server initiates the connection to l2gw agent with the entries in
    manager table in ovsdb hardware vtep schema.
    A configurable option 'enable_manager' in .ini file is provided so that
    the connection can be initiated by the ovsdb server or not based on boolean
    value.
    By default 'enable_manager' value is False, turn on the variable to True
    to initiate the connection from ovsdb server to l2gw agent.

    Closes-Bug:1466302

    Change-Id: Ib668ecda381367ea9f2f3cfa45e63d0e91e48f33