build: Don't allow --disable-daemon and --enable-appliance together.

This makes no sense, since the daemon is contained in the appliance so
you cannot build a (meaningful) appliance without having a daemon.
appliance: Remove conditionals in appliance/Makefile.am.

If appliance is disabled, the whole appliance/ subdirectory is
skipped.

If appliance is enabled, we can assume that the daemon is enabled too
(see previous commit) so we don't need the conditional code.  That
conditional code didn't work since the supermin 5 rewrite.
Add new logo to EXTRA_DIST.

This fixes commit d73531a0aa691ff961366afee4db2c99a40510b6.
Version 1.25.40.