pgsql: Add GUC log_temp_files to log the use of temporary files.

Log Message:
-----------
Add GUC log_temp_files to log the use of temporary files.

Bill Moran

Modified Files:
--------------
    pgsql/doc/src/sgml:
        config.sgml (r1.99 -> r1.100)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/config.sgml.diff?r1=1.99&r2=1.100)
    pgsql/src/backend/storage/file:
        fd.c (r1.132 -> r1.133)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/file/fd.c.diff?r1=1.132&r2=1.133)
    pgsql/src/backend/utils/misc:
        guc.c (r1.365 -> r1.366)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc.c.diff?r1=1.365&r2=1.366)
        postgresql.conf.sample (r1.199 -> r1.200)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/postgresql.conf.sample.diff?r1=1.199&r2=1.200)
    pgsql/src/include/utils:
        guc.h (r1.77 -> r1.78)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/guc.h.diff?r1=1.77&r2=1.78)