It's legal to call tpc_vote and tpc_finish multiple times.

Unfortutely, tpc_finish didn't handle this case correctly.

src/ZODB/BaseStorage.py

@@ -86,7 +86,7 @@
 """
 # Do this portably in the face of checking out with -kv
 import string
-__version__ = string.split('$Revision: 1.12 $')[-2:][0]
+__version__ = string.split('$Revision: 1.13 $')[-2:][0]
 
 import ThreadLock, bpthread
 import time, UndoLogCompatible
@@ -213,6 +213,7 @@ class BaseStorage(UndoLogCompatible.UndoLogCompatible):
         self._lock_acquire()
         try:
             if transaction is not self._transaction: return
+            try:
                 if f is not None: f()
 
                 u,d,e=self._ude
@@ -222,6 +223,7 @@ class BaseStorage(UndoLogCompatible.UndoLogCompatible):
                 self._ude=None
                 self._transaction=None
                 self._commit_lock_release()
+        finally:
             self._lock_release()
 
     def _finish(self, tid, u, d, e):