Adjust erc functions after previous erc-pre-send-function change

Adjust erc functions after previous erc-pre-send-function change

* lisp/erc/erc-goodies.el (noncommands): Use
erc-pre-send-functions instead of the hook.
(erc-send-distinguish-noncommands): Adjust function to new interface.

* lisp/erc/erc-ring.el (ring): Ditto.
(erc-add-to-input-ring): Ditto.

* lisp/erc/erc.el (erc-send-this): Really make obsolete.
(erc-pre-send-functions): Change to a list of functions to allow
erc-goodies and erc-ring to work as before.