pgsql: Move ident authentication code into auth.c along with the other

Log Message:
-----------
Move ident authentication code into auth.c along with the other authenciation
routines, leaving hba.c to deal only with processing the HBA specific files.

Modified Files:
--------------
pgsql/src/include/libpq:
hba.h (r1.47 -> r1.48)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/libpq/hba.h?r1=1.47&r2=1.48)
pgsql/src/backend/libpq:
auth.c (r1.165 -> r1.166)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/auth.c?r1=1.165&r2=1.166)
hba.c (r1.165 -> r1.166)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/hba.c?r1=1.165&r2=1.166)