Make number not available presentation also set screening to network provided.

Make number not available presentation also set screening to network provided.

Q.951 indicates that when the presentation indicator is "Number not
available due to interworking" for a number then the screening indicator
field should be "Network provided".

* Made ast_party_id_presentation() return AST_PRES_NUMBER_NOT_AVAILABLE
when the presentation is "Number not available due to interworking".  This
fix makes Asterisk consistent and it also makes it consistent with earlier
branches as far as this presentation value is concerned.

* Made pri_to_ast_presentation() and ast_to_pri_presentation() conversions
handle the "Number not available due to interworking" case better in
sig_pri.c.  This change is possible because the minimum required libpri
version (v1.4.11) has the necessary defines in libpri.h.
........

Merged revisions 360309 from http://svn.asterisk.org/svn/asterisk/branches/1.8

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10@360310 65c4cc65-6c06-0410-ace0-fbb531ad65f3