pgsql: Add configuration parameter ssl_renegotiation_limit to control

Log Message:
-----------
Add configuration parameter ssl_renegotiation_limit to control
how often we do SSL session key renegotiation. Can be set to
0 to disable renegotiation completely, which is required if
a broken SSL library is used (broken patches to CVE-2009-3555
a known cause) or when using a client library that can't do
renegotiation.

Tags:
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REL8_3_STABLE

Modified Files:
--------------
pgsql/doc/src/sgml:
config.sgml (r1.164.2.6 -> r1.164.2.7)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/config.sgml?r1=1.164.2.6&r2=1.164.2.7)
pgsql/src/backend/libpq:
be-secure.c (r1.83.2.3 -> r1.83.2.4)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/be-secure.c?r1=1.83.2.3&r2=1.83.2.4)
pgsql/src/backend/utils/misc:
guc.c (r1.432.2.6 -> r1.432.2.7)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc.c?r1=1.432.2.6&r2=1.432.2.7)
postgresql.conf.sample (r1.236 -> r1.236.2.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/postgresql.conf.sample?r1=1.236&r2=1.236.2.1)