Bug 1471 : Fixing the Open_vSwitch Schema Controller Table's Target as String (from Set<String>)

Also added a IT test to cover this case.
This issue was uncovered while fixing https://git.opendaylight.org/gerrit/#/c/9606

Change-Id: Icf1b242f65a58aa6a38259ee0f7195d1ec946d7c
Signed-off-by: Madhu Venugopal <mavenugo@gmail.com>
Merge "Bug 1471 : Fixing the Open_vSwitch Schema Controller Table's Target as String (from Set<String>)"