Updated chan_dahdi.c and sig_wat.c to support wat_debug as config option

This modifications were already present in previous Asterisk versions

This are modifications done manually exclusively for Asterisk 11 as when
I did the initial import and then applied Asterisk 10 patch, the Asterisk
patch I applied was not the latest on the git repo (it was the latest released)
and they did not contain this modifications for wat_debug