V2V: Fix some problems

1.Default cases in tests.cfg is v2v_quick which contains only three tests.
   To list them all with run script, adding another v2v_all content.
2.For remote host, if its language is not en.US, pool_exists will return False.
   Then pool will be not undefined.So do some changes.
3.Options for virt-v2v have fixed network to "-n", now support "-b".
4.Add mk_label function for creating disk pool, because unlabelled disk can not be used for pool.
OK, how about this:
```
# Undefine pool anyway
 try:
     self.virsh_instance.pool_undefine(name, ignore_status=False)
 except error.CmdError, detail:
     logging.error("Undefine pool '%s' failed:%s", name, detail)
+    if self.pool_exists(name):
+         return False
```
Of course, this is just a  temporary solution. It needs to take more consideration. :(