Cope with missing configuration information inside the configuration method.

This allows us to better recover if the store has been deleted.

Signed-off-by: Ewan Mellor <ewan@xensource.com>

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

@@ -69,8 +69,10 @@ class BlkifController(DevController):
                                                   'dev', 'type', 'params',
                                                   'read-only')
 
-        result.append(['dev', dev])
-        result.append(['uname', typ + ":" + params])
+        if dev:
+            result.append(['dev', dev])
+        if typ and params:
+            result.append(['uname', typ + ":" + params])
         if ro:
             result.append(['mode', 'r'])
         else:

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

@@ -80,11 +80,15 @@ class NetifController(DevController):
                                                      'script', 'ip', 'bridge',
                                                      'mac')
 
-        result.append(['script',
-                       script.replace(xroot.network_script_dir + os.sep, "")])
+        if script:
+            result.append(['script',
+                           script.replace(xroot.network_script_dir + os.sep,
+                                          "")])
         if ip:
             result.append(['ip', ip.split(" ")])
-        result.append(['bridge', bridge])
-        result.append(['mac', mac])
+        if bridge:
+            result.append(['bridge', bridge])
+        if mac:
+            result.append(['mac', mac])
 
         return result