strptime(): The code that was adding 12 to PM hours was incorrect because it added it to 12 PM too.  12 PM should be hour 12 not hour 24.
strptime(): The code that was adding 12 to PM hours was incorrect
because it added it to 12 PM too.  12 PM should be hour 12 not hour
24.

Also cleaned up a minor style nit.  There are more style problems in
this file that I'll clean up next (but I didn't want them to overwhelm
the substance of this fix).

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