Fix logging in store().

The ImmediateCommitStrategy storage is not a ZEOStorage, but a FileStorage.

src/ZEO/StorageServer.py

@@ -483,7 +483,7 @@ class ImmediateCommitStrategy:
         except Exception:
             # Unexpected storage errors are logged and passed to the client
             exc_info = sys.exc_info()
-            self.storage._log("store error: %s, %s" % exc_info[:2],
+            log("store error: %s, %s" % exc_info[:2],
                 zLOG.ERROR, error=exc_info)
             newserial = exc_info[1]
             del exc_info
@@ -495,7 +495,7 @@ class ImmediateCommitStrategy:
             dump(newserial, 1)
         except:
             msg = "Couldn't pickle storage exception: %s" % repr(newserial)
-            self.storage._log(msg, zLOG.ERROR)
+            log(msg, zLOG.ERROR)
             dump('', 1) # clear pickler
             r = StorageServerError(msg)
             newserial = r