dispatch: verify result of early command parsing
Before, early options were stripped from args, and because of this, some
kind of parsing errors weren't reported. For example,
$ hg ci -m -Ra file
would execute "hg ci -m file" in repository "a".
This patch fixes the issue by parsing early options again by real getopt-based
parser, and verifying the results. If the early parsing appears wrong, hg just
aborts. The current error message seems not nice, and should be improved, maybe
in V2 or follow-up.
Note that this isn't a security feature because we can still do anything by
using shell aliases.
ERROR: FIXME: This is a known failure of filelog.size for data starting with \1\n
OK.