avahi: fix packaging of avahi-autoipd

avahi: fix packaging of avahi-autoipd

- Avahi's "avahi-autoipd" file is in the dhcp/ folder, not dhcp3/
- udhcpc files were being installed but not being shipped in avahi-autoipd
- do_install override for avahi-autoipd was not being called and is not
  required, so join it into regular do_install.
- While at it, fixup string quoting in description.

This makes avahi-autoipd work with simple ifup/down scripts.

(From OE-Core rev: 172e663f1b00733cf956cb118d7a5e1a252c1671)

Signed-off-by: Marc Reilly <marc@cpdesign.com.au>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>