[Serusers] added domain_suffix parameter to enum_query

[Juha Heinanen]

some folks have asked domain_suffix as a parameter to enum_query.  i
just committed some changes for that purpose.

the syntax now is (from README):

1.4.1. enum_query(), enum_query("suffix"), enum_query("suffix", "service")
 
   Replaces the current Request-URI with the result of a successful enum
   query on the user part of the current Request-URI, which is assumed
   to be of the form +up-to-15-decimal-digits. An NAPTR record whose
   flags field has string value "u" and whose services field has string
   value "e2u+service:sip" or "e2u+sip" (if "service" parameter is not
   given) is looked for. Returns -1 if enum_query fails and 1 otherwise.
 
   If "suffix" parameter is not given, value of domain_suffix module
   paremeter is used.
 
   Example 1-2. enum_query usage
...
enum_query("e164.foo.com.");
...

i did some testing on the first two versions of the call and it seemed
to work.  i didn't test the last version.

this is in unstable. let me know if you find problems.

-- juha