pgsql: SSL improvements: o read global SSL configuration file o add

Log Message:
-----------
SSL improvements:

    o read global SSL configuration file
    o add GUC "ssl_ciphers" to control allowed ciphers
    o add libpq environment variable PGSSLKEY to control SSL hardware keys

Victor B. Wagner

Modified Files:
--------------
    pgsql/doc/src/sgml:
        config.sgml (r1.110 -> r1.111)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/config.sgml.diff?r1=1.110&r2=1.111)
        libpq.sgml (r1.228 -> r1.229)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/libpq.sgml.diff?r1=1.228&r2=1.229)
        runtime.sgml (r1.376 -> r1.377)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/runtime.sgml.diff?r1=1.376&r2=1.377)
    pgsql/src/backend/libpq:
        be-secure.c (r1.77 -> r1.78)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/be-secure.c.diff?r1=1.77&r2=1.78)
    pgsql/src/backend/postmaster:
        postmaster.c (r1.523 -> r1.524)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/postmaster.c.diff?r1=1.523&r2=1.524)
    pgsql/src/backend/utils/misc:
        guc.c (r1.374 -> r1.375)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc.c.diff?r1=1.374&r2=1.375)
        postgresql.conf.sample (r1.207 -> r1.208)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/postgresql.conf.sample.diff?r1=1.207&r2=1.208)
    pgsql/src/include/postmaster:
        postmaster.h (r1.15 -> r1.16)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/postmaster/postmaster.h.diff?r1=1.15&r2=1.16)
    pgsql/src/interfaces/libpq:
        fe-secure.c (r1.92 -> r1.93)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-secure.c.diff?r1=1.92&r2=1.93)