*: Don't emit warnings on loadBefore

@d-maurer suggests to keep loadBefore without deprecation
(https://github.com/zopefoundation/ZODB/pull/323#pullrequestreview-650963363).

-> Don't emit warnings about deprecating loadBefore.

-> Keep the deprecation text in loadBefore interface, since loadBeforeEx
   should practically provide wider functionality without putting
   unnecessary constraint on storage implementations. In other words
   loadBefore deprecation is still there, but less aggressively
   advertised with the idea to make transition for outside-of-ZODB code
   to loadBeforeEx more smooth and with a bit more steps (we might want
   to reinstate the deprecation warnings at a later time).

src/ZODB/DemoStorage.py

@@ -24,7 +24,6 @@ import os
 import random
 import weakref
 import tempfile
-import warnings
 import ZODB.BaseStorage
 import ZODB.blob
 import ZODB.interfaces
@@ -228,9 +227,6 @@ class DemoStorage(ConflictResolvingStorage):
         return ZODB.utils.loadBeforeEx(self.base, oid, before)
 
     def loadBefore(self, oid, before):
-        warnings.warn("loadBefore is deprecated - use loadBeforeEx instead",
-                DeprecationWarning, stacklevel=2)
-
         data, serial = self.loadBeforeEx(oid, before)
 
         # find out next_serial.

src/ZODB/FileStorage/FileStorage.py

@@ -21,7 +21,6 @@ import errno
 import logging
 import os
 import time
-import warnings
 from struct import pack
 from struct import unpack
 
@@ -594,8 +593,6 @@ class FileStorage(
                 return None, h.tid
 
     def loadBefore(self, oid, tid):
-        warnings.warn("loadBefore is deprecated - use loadBeforeEx instead",
-                DeprecationWarning, stacklevel=2)
         with self._files.get() as _file:
             pos = self._lookup_pos(oid)
             end_tid = None

src/ZODB/MappingStorage.py

@@ -19,7 +19,6 @@ storage without distracting storage details.
 
 import BTrees
 import time
-import warnings
 import ZODB.BaseStorage
 import ZODB.interfaces
 import ZODB.POSException
@@ -169,8 +168,6 @@ class MappingStorage(object):
     # ZODB.interfaces.IStorage
     @ZODB.utils.locked(opened)
     def loadBefore(self, oid, tid):
-        warnings.warn("loadBefore is deprecated - use loadBeforeEx instead",
-                DeprecationWarning, stacklevel=2)
         tid_data = self._data.get(oid)
         if tid_data:
             before = ZODB.utils.u64(tid)

src/ZODB/tests/testConnection.py

@@ -1322,8 +1322,6 @@ class StubStorage(object):
         return data, serial
 
     def loadBefore(self, oid, tid):
-        warnings.warn("loadBefore is deprecated - use loadBeforeEx instead",
-                DeprecationWarning, stacklevel=2)
         return self._data[oid] + (None, )
 
     def store(self, oid, serial, p, version, transaction):

src/ZODB/tests/test_storage.py

@@ -20,7 +20,6 @@ storage tests against the test storage.
 """
 import bisect
 import unittest
-import warnings
 
 from ZODB.BaseStorage import BaseStorage
 from ZODB import POSException
@@ -106,11 +105,6 @@ class MinimalMemoryStorage(BaseStorage, object):
             self._ltid = self._tid
 
     def loadBefore(self, the_oid, the_tid):
-        warnings.warn("loadBefore is deprecated - use loadBeforeEx instead",
-                DeprecationWarning, stacklevel=2)
-        return self._loadBefore(the_oid, the_tid)
-
-    def _loadBefore(self, the_oid, the_tid):
         # It's okay if loadBefore() is really expensive, because this
         # storage is just used for testing.
         with self._lock:
@@ -134,7 +128,7 @@ class MinimalMemoryStorage(BaseStorage, object):
 
     def loadBeforeEx(self, oid, before):
         try:
-            r = self._loadBefore(oid, before)
+            r = self.loadBefore(oid, before)
         except KeyError:
             return None, z64
         if r is None: