options: add special -leak-report option

options: add special -leak-report option

Add a special option "-leak-report" that enables talloc leak
reporting.  It only works if it's given as the first argument.

The code abuses the CONF_TYPE_PRINT option type to make main option
parsing ignore the option. The parser incorrectly consumed the
following commandline argument as a "parameter" for options of this
type when they had the flag to not exit after printing the message.
Fix this. It makes no difference for any previously existing option I
think.