Fix a few minor man formatting consistency issues

Some flags ended with a colon, some didn't.  For man pages, the prevailing normal practice is not to end the flags lines with colons.

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Merge pull request #5071 from tianon/minor-man-formatting-consistency

Fix a few minor man formatting consistency issues