A 'tls' statement can be specified both for individual addresses
and for the whole list (as a default value when an individual
address doesn't have its own 'tls' set), just as it was done
before for the 'port' value.
Create a new function 'print_rawqstring()' to print a string residing
in a 'isc_textregion_t' type parameter.
Create a new function 'copy_string()' to copy a string from a
'cfg_obj_t' object into a 'isc_textregion_t'.