Make sure the temporary savepoint storage is closed properly.

src/ZODB/Connection.py

@@ -1099,7 +1099,7 @@ class Connection(ExportImport, object):
         src = self._savepoint_storage
         self._storage = self._normal_storage
         self._savepoint_storage = None
-
+        try:
             self._log.debug("Committing savepoints of size %s", src.getSize())
             oids = src.index.keys()
 
@@ -1111,11 +1111,13 @@ class Connection(ExportImport, object):
                 data, serial = src.load(oid, src)
                 obj = self._cache.get(oid, None)
                 if obj is not None:
-                self._cache.update_object_size_estimation(obj._p_oid, len(data))
+                    self._cache.update_object_size_estimation(
+                        obj._p_oid, len(data))
                     obj._p_estimated_size = len(data)
                 if isinstance(self._reader.getGhost(data), Blob):
                     blobfilename = src.loadBlob(oid, serial)
-                s = self._storage.storeBlob(oid, serial, data, blobfilename,
+                    s = self._storage.storeBlob(
+                        oid, serial, data, blobfilename,
                         '', transaction)
                     # we invalidate the object here in order to ensure
                     # that that the next attribute access of its name
@@ -1127,6 +1129,7 @@ class Connection(ExportImport, object):
                                             '', transaction)
 
                 self._handle_serial(oid, s, change=False)
+        finally:
             src.close()
 
     def _abort_savepoint(self):