Use config-package-dev for awesome wrapper script.

This gets rid of the custom maintainer scripts:
 8 files changed, 13 insertions(+), 47 deletions(-)

I've tested that it installs and works fine (and purges fine...) on my machine. I _think_ the upgrade process will work fine, though note that config-package-dev does the diversion in postinst/prerm instead of preinst/postrm (since it installs to a different name, and drops an unpackaged symlink in place in the postinst, which avoids a couple of problems) -- I think the old postrm will run before the new unpack before the new postinst, though.