MODE: don't report error on "more modes than parameters"

Don't report ERR_NEEDMOREPARAMS(461) when a MDOE command with more modes
than nicknames is handled, as well as for channel limit and key changes
without specifying the limit or key parameters.

This is how a lot (all?) other IRC servers behave, including ircd2.11,
InspIRCd, and ircd-seven. And because of clients (tested with Textual and
mIRC) sending bogus MODE commands like "MODE -ooo nick", end-users got the
expected result as well as correct but misleading error messages ...

If ngIRCd is compiled using "strict mode", these errors are still reported.

Reported-by: Tim <tim@stackwatch.net>