Remove try/except block that hide an exception without explanations.

KeyError may be raised from many statements here, the try/except give no indications.
Also reduce block indentation for readability and add some comments.

git-svn-id: https://svn.erp5.org/repos/neo/trunk@1469 71dcc9de-d417-0410-9af5-da40c76e7ee4

neo/master/handlers/storage.py

@@ -60,9 +60,12 @@ class StorageServiceHandler(BaseServiceHandler):
         if tid > self.app.tm.getLastTID():
             raise UnexpectedPacketError
 
-        try:
+        # transaction locked on this storage node
         t = self.app.tm[tid]
-            if t.lock(uuid): # all nodes are locked
+        if not t.lock(uuid): 
+            return
+
+        # all nodes are locked
         # XXX: review needed:
         # don't iterate over connections but search by uuid
         # include client's uuid in Transaction object
@@ -80,17 +83,13 @@ class StorageServiceHandler(BaseServiceHandler):
                         p = Packets.NotifyTransactionFinished(tid)
                         c.answer(p, t.getMessageId())
                     else:
-                                p = Packets.InvalidateObjects(t.getOIDList(),
-                                        tid)
-                                c.notify(p)
+                        c.notify(Packets.InvalidateObjects(t.getOIDList(), tid))
                 elif node.isStorage():
                     if uuid in t.getUUIDList():
-                                p = Packets.UnlockInformation(tid)
-                                c.notify(p)
+                        c.notify(Packets.UnlockInformation(tid))
+
+        # remove transaction from manager
         self.app.tm.remove(tid)
-        except KeyError:
-            # What is this?
-            pass
 
     def notifyReplicationDone(self, conn, packet, offset):
         uuid = conn.getUUID()