[XEND] Compare result of blkdev_name_to_number() explicitly against None.

Signed-off-by: Keir Fraser <keir@xensource.com>

tools/python/xen/util/blkif.py

@@ -52,7 +52,7 @@ def blkdev_segment(name):
     """
     val = None
     n = blkdev_name_to_number(name)
-    if n:
+    if not n is None:
         val = { 'device'       : n,
                 'start_sector' : long(0),
                 'nr_sectors'   : long(1L<<63),

tools/python/xen/xend/server/blkif.py

@@ -80,7 +80,7 @@ class BlkifController(DevController):
                          'acm_policy' : policy})
 
         devid = blkif.blkdev_name_to_number(dev)
-        if not devid:
+        if devid is None:
             raise VmError('Unable to find number for device (%s)' % (dev))
 
         front = { 'virtual-device' : "%i" % devid,