bug#13506: 24.3.50; loading emacsbug.el ignores customized `send-mail-function'

[Drew Adams <drew.adams@oracle.com>]

> > I just discovered that if you have customized `send-mail-function'
> > to `mailclient-send-it', but you load that customization after
> > loading `emacsbug.el[c]' (for whatever reason), then your user
> > setting is simply ignored.
> 
> `message-send-mail-function' is the variable to customize here, I
> think?

Why?  And why is that relevant, even if true?

,----
| send-mail-function is a variable defined in `sendmail.el'.
| Its value is mailclient-send-it
| Original value was sendmail-query-once
| 
|   This variable can be risky when used as a file-local variable.
| 
| Documentation:
| Function to call to send the current buffer as mail.
| The headers should be delimited by a line which is
| not a valid RFC822 header or continuation line,
| that matches the variable `mail-header-separator'.
| This is used by the default mail-sending commands.  See also
| `message-send-mail-function' for use with the Message package.
| 
| You can customize this variable.
| 
| This variable was introduced, or its default value was changed, in
| version 24.1 of Emacs.
`----