pgsql: Add a "relistemp" boolean column to pg_class, which is true for

Log Message:
-----------
Add a "relistemp" boolean column to pg_class, which is true for temporary
relations (including a temp table's indexes and toast table/index), and
false for normal relations. For ease of checking, this commit just adds
the column and fills it correctly --- revising the relation access machinery
to use it will come separately.

Modified Files:
--------------
pgsql/doc/src/sgml:
catalogs.sgml (r2.199 -> r2.200)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/catalogs.sgml?r1=2.199&r2=2.200)
pgsql/src/backend/catalog:
heap.c (r1.351 -> r1.352)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/heap.c?r1=1.351&r2=1.352)
pgsql/src/backend/utils/cache:
relcache.c (r1.284 -> r1.285)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/cache/relcache.c?r1=1.284&r2=1.285)
pgsql/src/include/catalog:
catversion.h (r1.526 -> r1.527)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h?r1=1.526&r2=1.527)
pg_attribute.h (r1.146 -> r1.147)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_attribute.h?r1=1.146&r2=1.147)
pg_class.h (r1.112 -> r1.113)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_class.h?r1=1.112&r2=1.113)