subtree: disallow --no-{help,quiet,debug,branch,message}

subtree: disallow --no-{help,quiet,debug,branch,message}

"git subtree" only handles the negated variant of the options annotate,
prefix, onto, rejoin, ignore-joins and squash explicitly.  help is
handled by "git rev-parse --parseopt" implicitly, but not its negated
form.  Disable negation for it and the for the rest of the options to
get a helpful error message when trying them.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>