merge emacs-pretest-bug and emacs-devel

[Glenn Morris]

This has come up before at least once...

Given the way the pretest-bug list is being used, there is little
point having it. Indeed, it often causes extra work, with discussions
split on two lists.

When making emacs-pretest-bug an alias for emacs-devel was proposed in
March those who replied were in favour, but it never happened:

http://lists.gnu.org/archive/html/emacs-devel/2007-03/msg00344.html
  From:     Richard Stallman
  Subject:  Emacs pretest bug reports
  Date:     Tue, 06 Mar 2007 17:36:33 -0500