Remove audio choices that are irrelevant on OpenBSD.

Index: config.example.in
--- config.example.in.orig
+++ config.example.in
@@ -121,32 +121,10 @@
 #
 #HTTPProxy =
 
-# Sound driver - OSS, ALSA, JACK, SNDIO (on OpenBSD) or null (only for
+# Sound driver - SNDIO (on OpenBSD) or null (only for
 # debugging).  You can enter more than one driver as a colon-separated
 # list.  The first working driver will be used.
 #SoundDriver = @SOUNDDRIVER@
-
-# Jack output settings.
-#JackClientName = "moc"
-#JackStartServer = no
-#JackOutLeft = "system:playback_1"
-#JackOutRight = "system:playback_2"
-
-# OSS output settings.
-#OSSDevice = /dev/dsp
-#OSSMixerDevice = /dev/mixer
-#OSSMixerChannel1 = pcm             # 'pcm', 'master' or 'speaker'
-#OSSMixerChannel2 = master          # 'pcm', 'master' or 'speaker'
-
-# ALSA output settings.  If you need to dump the audio produced by MOC
-# to a file for diagnostic purposes, the following setting of 'ALSADevice'
-# should do that:
-#
-#    ALSADevice=tee:hw,'/tmp/out.wav',wav
-#
-#ALSADevice = default
-#ALSAMixer1 = PCM
-#ALSAMixer2 = Master
 
 # Under some circumstances on 32-bit systems, audio played continously
 # for long periods of time may begin to stutter.  Setting this option to