Fixed UbuntuOSMountTools inheritance

Due to this bug, the linux OS mounting code was never used in the Ubuntu OS
mounting code.

coriolis/osmorphing/osmount/ubuntu.py

@@ -9,7 +9,7 @@ from coriolis import utils
 LOG = logging.getLogger(__name__)
 
 
-class UbuntuOSMountTools(base.BaseSSHOSMountTools):
+class UbuntuOSMountTools(base.BaseLinuxOSMountTools):
     def check_os(self):
         os_info = utils.get_linux_os_info(self._ssh)
         if os_info and os_info[0] == 'Ubuntu':