pgsql: Clean up libpq's pollution of application namespace by renaming

Log Message:
-----------
Clean up libpq's pollution of application namespace by renaming the
exported routines of ip.c, md5.c, and fe-auth.c to begin with 'pg_'.
Also get rid of the vestigial fe_setauthsvc/fe_getauthsvc routines
altogether.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        libpq.sgml (r1.193 -> r1.194)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/libpq.sgml.diff?r1=1.193&r2=1.194)
    pgsql/src/backend/commands:
        user.c (r1.161 -> r1.162)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/user.c.diff?r1=1.161&r2=1.162)
    pgsql/src/backend/libpq:
        auth.c (r1.131 -> r1.132)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/auth.c.diff?r1=1.131&r2=1.132)
        crypt.c (r1.66 -> r1.67)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/crypt.c.diff?r1=1.66&r2=1.67)
        hba.c (r1.148 -> r1.149)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/hba.c.diff?r1=1.148&r2=1.149)
        ip.c (r1.31 -> r1.32)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/ip.c.diff?r1=1.31&r2=1.32)
        md5.c (r1.29 -> r1.30)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/md5.c.diff?r1=1.29&r2=1.30)
        pqcomm.c (r1.181 -> r1.182)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/pqcomm.c.diff?r1=1.181&r2=1.182)
    pgsql/src/backend/postmaster:
        pgstat.c (r1.110 -> r1.111)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/pgstat.c.diff?r1=1.110&r2=1.111)
        postmaster.c (r1.469 -> r1.470)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/postmaster.c.diff?r1=1.469&r2=1.470)
    pgsql/src/backend/utils/adt:
        network.c (r1.55 -> r1.56)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/network.c.diff?r1=1.55&r2=1.56)
        pgstatfuncs.c (r1.25 -> r1.26)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/pgstatfuncs.c.diff?r1=1.25&r2=1.26)
        varlena.c (r1.136 -> r1.137)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/varlena.c.diff?r1=1.136&r2=1.137)
    pgsql/src/include/libpq:
        auth.h (r1.30 -> r1.31)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/libpq/auth.h.diff?r1=1.30&r2=1.31)
        crypt.h (r1.31 -> r1.32)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/libpq/crypt.h.diff?r1=1.31&r2=1.32)
        ip.h (r1.14 -> r1.15)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/libpq/ip.h.diff?r1=1.14&r2=1.15)
    pgsql/src/interfaces/libpq:
        fe-auth.c (r1.105 -> r1.106)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-auth.c.diff?r1=1.105&r2=1.106)
        fe-auth.h (r1.22 -> r1.23)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-auth.h.diff?r1=1.22&r2=1.23)
        fe-connect.c (r1.322 -> r1.323)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-connect.c.diff?r1=1.322&r2=1.323)