miscellaneous: clean up trailing whitespace once again

miscellaneous: clean up trailing whitespace once again

An earlier commit attempted to cleanse our environment
of all useless trailing whitespace. But the effort did
not catch 'empty' lines with a single space before ^J.

This commit hopefully finishes off the earlier effort.
In the meantime, let's pray that contributors' editors
are configured so that such wasted crap is disallowed!

Reference(s):
commit fe75e26ab64dab88762230db0797e765507b73ac

Signed-off-by: Jim Warner <james.warner@comcast.net>