Remove duplicated tests for check_ovs_vxlan_version

test_ovs_lib, test_ovs_neutron_agent and test_ofa_neutron_agent
have duplicated same unit tests for check_ovs_vxlan_version.
This commits removes tests from ovs/ofa_neutron_agent.

Change-Id: Ia028a4afc1c8154f895187c979d23b626ab4ae3a
Closes-Bug: #1301337
Set the log level to debug for loading extensions

Setting the log level to debug instead of info
for load extension file.

Change-Id: Ia2322a5d62381f15b4bf4e0bb7120813be985786
Merge "Remove duplicated tests for check_ovs_vxlan_version"
Merge "Set the log level to debug for loading extensions"