sysfs: restored legacy names /etc/dahdi/<channo>:

Update dahdi.rules to create again the old fashioned device files
(/dev/dahdi/<channo>), but as symlinks to modern names.

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
Acked-by: Russ Meyerriecks <rmeyerriecks@digium.com>

dahdi.rules

@@ -1,4 +1,9 @@
 # DAHDI devices with ownership/permissions for running as non-root
 SUBSYSTEM=="dahdi",		OWNER="asterisk", GROUP="asterisk", MODE="0660"
+
+# Backward compat names: /dev/dahdi/<channo>
+SUBSYSTEM=="dahdi_channels",	SYMLINK+="dahdi/%m"
+
+# hotplug support
 SUBSYSTEM=="dahdi_devices",	RUN="/usr/share/dahdi/handle_device"
 SUBSYSTEM=="dahdi_spans",	RUN="/usr/share/dahdi/span_config"