package: asterisk: osp.conf and sip.conf no longer exist

Signed-off-by: Phil Sutter <phil@nwl.cc>

package/asterisk/files/asterisk.conffiles

@@ -12,7 +12,5 @@
 /etc/asterisk/manager.conf
 /etc/asterisk/modules.conf
 /etc/asterisk/musiconhold.conf
-/etc/asterisk/osp.conf
 /etc/asterisk/queues.conf
 /etc/asterisk/rtp.conf
-/etc/asterisk/sip.conf