Disable use of BerkeleyDB 4.6.x to see what the odd platform buildbots

think.  In particular, neal norwitz has traced an Ubuntu sparc64 crash
to the Lib/test/bsddb/test_basics.py test when opening a db with DB_THREAD.

setup.py

@@ -681,7 +681,10 @@ class PyBuildExt(build_ext):
         # a release.  Most open source OSes come with one or more
         # versions of BerkeleyDB already installed.
 
-        max_db_ver = (4, 6)
+        max_db_ver = (4, 5)  # XXX(gregory.p.smith): 4.6 "works" but seems to
+                             # have issues on many platforms.  I've temporarily
+                             # disabled 4.6 to see what the odd platform
+                             # buildbots say.
         min_db_ver = (3, 3)
         db_setup_debug = False   # verbose debug prints from this script?