CommandLineParser cannot handle values being passed to boolean options

[Raymond Wagner]

If an option/value pair is processed, split using a equals ('=') sign, and passed to a boolean option, the parser will attempt to reprocess the two arguments separately, and get caught in an infinite loop.

[Raymond Wagner <rwagner@…>]

In 168b8528f39ef8837884f93d8c26f3496868c642/mythtv:

Fix infinite reprocessing loop for booleans in command line parser.

This fixes the immediate issue, by allowing the parser loop to
distinguish between the two scenarios, and only attempt reprocessing if
it makes sense to.

Refs #11642

I'm leaving the ticket open, as we should not be reporting an error
prematurely when we're going to attempt reprocessing. We should probably
also accept various forms of "true" and "false" for booleans, rather
than accept no values.

[Stuart Auchterlonie]

Closing out old tickets.