Ignore testGetOpenflowVersion: it is no longer applicable

The openFlow version is now determined by configuration's getProperty("ovsdb.of.version", "1.3").
Thus, the ovs version attribute (returned by ovs' OpenVSwitch table) is not used to determine what is
the openFlow version chosen by netVirtConfigurationService.

See: https://git.opendaylight.org/gerrit/#/c/11084/
     https://github.com/opendaylight/ovsdb/commit/2bc58c9cca16dc3e389cdfc18593578748fd52d5

Patch 2: include Sam's feedback

Change-Id: Icf4f3f633b2131a4521ef2509c02bcb0c7223abf
Signed-off-by: Flavio Fernandes <ffernand@redhat.com>
(cherry picked from commit f3f890d63abbdff59c2950371785fc760b658b54)