Added support for bridge other-config.

This patch will Create/update other-config to bridges.
To add other-config in bridge, run the following commands -

sudo ovs-vsctl -- set Bridge br0 other_config:enable-input=false

This assumes a bridge exists with name br0
other-config is a key/value pair, and AFAIK, it can be any random key/value.
To update/modify other config, just supply a new value like -

sudo ovs-vsctl -- set Bridge br0 other_config:enable-input=yes

Change-Id: I4cafe9b8c74f752d951ea073b0a9766721452b6d
Signed-off-by: Sharad Mishra <sharad.d.mishra@intel.com>