Windows: vm_helper.get_udf_path_name may be replacing slashes wrongly

Right now we have this comment in the method:

     61 # the head has to be a canonical path that uses / as the separator
     62 # because is information used by the server side to create the file it
     63 # it correct location.
     64 head = head.replace('/', '\\')
     65 return head, tail

On one hand, I think we need to do the opposite replace. On the other hand, by looking how the volume_manager uses this functionality, we should not be replacing the slashes at all. We need to define 2 methods, one that calculate the suggested path (canonical form for the server) from any path, and another that computes the udf real (native) path and udf name:

(edit to see proper spacing)

   1204 try:
   1205 udf_path, udf_name = get_udf_path_name(path)
   1206 except ValueError, e:
   1207 self.m.event_q.push('VM_UDF_CREATE_ERROR', path=path,
   1208 error="INVALID_PATH: %s" % (e,))
   1209 else:
   1210 try:
   1211 marker = MDMarker(path)
   ...
   1217 udf = UDF(None, None,
   1218 # suggested_path is always unicode, because the
   1219 # suggested path is a server side metadata we will
   1220 # always use the unix path separator /
   1221 (udf_path + '/' + udf_name).decode('utf-8'),
   1222 # always subscribed since it's a local request
   1223 path, subscribed=True)
   1224 self.marker_udf_map[marker] = udf
   1225 self.m.action_q.create_udf(udf_path.decode('utf-8'),
   1226 udf_name.decode('utf-8'), marker)
   1227 except Exception, e:
   1228 self.m.event_q.push('VM_UDF_CREATE_ERROR', path=path,
   1229 error="UNKNOWN_ERROR: %s" % (e,))