pgsql: Rename pg_complete_relation_size() to pg_total_relation_size(),

Log Message:
-----------
Rename pg_complete_relation_size() to pg_total_relation_size(), for the
sake of brevity and clarity.

Make pg_reload_conf(), pg_rotate_logfile(), and pg_cancel_backend()
return a boolean rather than an integer to indicate success or failure.

Along the way, make some minor cleanups to dbsize.c -- in particular,
use elog() rather than ereport() for "shouldn't happen" error
conditions, and remove some of the more flagrant violations of the
Postgres indentation conventions.

Catalog version bumped.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        func.sgml (r1.285 -> r1.286)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml.diff?r1=1.285&r2=1.286)
        release.sgml (r1.368 -> r1.369)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/release.sgml.diff?r1=1.368&r2=1.369)
    pgsql/src/backend/utils/adt:
        dbsize.c (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/dbsize.c.diff?r1=1.3&r2=1.4)
        misc.c (r1.47 -> r1.48)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/misc.c.diff?r1=1.47&r2=1.48)
    pgsql/src/include/catalog:
        catversion.h (r1.301 -> r1.302)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h.diff?r1=1.301&r2=1.302)
        pg_proc.h (r1.384 -> r1.385)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h.diff?r1=1.384&r2=1.385)
    pgsql/src/include/utils:
        builtins.h (r1.263 -> r1.264)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/builtins.h.diff?r1=1.263&r2=1.264)