In DAHDI-Linux 2.7 the layout of the /dev/dahdi files changes so that they are
grouped by span. When opening channels by number all utilities need to use
DAHDI_SPECIFY now.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>