merge of r58091 from trunk:
merge of r58091 from trunk:

Don't allow BerkeleyDB 4.6.x as the current 4.6.19 release is prone
to lockups.  We'll reenable it once a good 4.6.x release exists.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator