Remove redundant imports of ZODB.

A ZODB import is only redundant if it is not used and does not
precede an import from Persistence.

lib/python/Products/ZCTextIndex/CosineIndex.py

@@ -23,8 +23,6 @@ from Products.ZCTextIndex.BaseIndex import BaseIndex, \
                                            inverse_doc_frequency, \
                                            scaled_int, SCALE_FACTOR
 
-import ZODB
-
 class CosineIndex(BaseIndex):
 
     __implements__ = IIndex

lib/python/Products/ZCTextIndex/OkapiIndex.py

@@ -24,8 +24,6 @@ from Products.ZCTextIndex.BaseIndex import BaseIndex, \
                                            inverse_doc_frequency, \
                                            scaled_int
 
-import ZODB
-
 class OkapiIndex(BaseIndex):
 
     __implements__ = IIndex