configure.ac: Remove line only used for debugging.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Installation: do not install notification files if not configured

Man page and autostart desktop link for skyldavnotify shall
not be installed if configured with
--with-notification=no

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>