Output the current trunk_type in "add X-channel vs. trunk_type" error messages and
check this for B-/D-channels too.
ISDN (= digital) spans need to have a trunk_type set before adding channels,
bail out early with an error message (actually two) if this is not the case.
(Adding channels should really be moved out of the parsing loop, to catch
certain types of errors easier.)
Signed-off-by: Stefan Knoblich <stkn@openisdn.net>
ab285ace3d