parse-options: move NODASH sanity checks to parse_options_check

parse-options: move NODASH sanity checks to parse_options_check

A dashless switch (like '(' passed to 'git grep') cannot be negated,
cannot be attached to an argument, and cannot have a long form.
Currently parse-options runs the related sanity checks when the
dashless option is used; better to always check them at the start of
option parsing, so mistakes can be caught more quickly.

The error message at the new call site is less specific about the
nature of the error, for simplicity.  On the other hand, it prints
which switch was problematic.  Before:

	fatal: BUG: dashless options can't be long

After:

	error: BUG: switch '(' uses feature not supported for dashless options

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>