Log Message:
-----------
Install safeguard against running PL/Python 2 and 3 in the same session
Modified Files:
--------------
pgsql/doc/src/sgml:
plpython.sgml (r1.50 -> r1.51)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/plpython.sgml?r1=1.50&r2=1.51)
pgsql/src/pl/plpython:
plpython.c (r1.146 -> r1.147)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpython/plpython.c?r1=1.146&r2=1.147)