54687: fix brace completion

% mkdir 'a b c'; touch 'a b c'/{'a b c','d e f'}
% ls a\ b\ c/{<tab>
corrupts the command line into
% ls a\ b\ {c/
and the effect is worse the more backslashes there are. It seems like
this code should simply always use bp->qpos so there is no reason to
keep hasunqu around either.

For the compctl path, the curpos members need to be whatever they're
determined to be at the start by addwhat for the comparison with ppl and
psl, so just fix them at the end before add_match_data.

The quotename in get_comp_string fixes subsequent completions, eg
% ls a\ b\ c/{a\ b\ c,<tab>

0 files changed, 0 insertions, 0 deletions