pgsql-server: Rename vacuum_cost_naptime to vacuum_cost_delay, with

Log Message:
-----------
Rename vacuum_cost_naptime to vacuum_cost_delay, with agreement from Jan.

Modified Files:
--------------
    pgsql-server/doc/src/sgml:
        runtime.sgml (r1.272 -> r1.273)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/doc/src/sgml/runtime.sgml.diff?r1=1.272&r2=1.273)
    pgsql-server/src/backend/commands:
        vacuum.c (r1.285 -> r1.286)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/commands/vacuum.c.diff?r1=1.285&r2=1.286)
    pgsql-server/src/backend/po:
        af.po (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/po/af.po.diff?r1=1.1&r2=1.2)
        sv.po (r1.20 -> r1.21)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/po/sv.po.diff?r1=1.20&r2=1.21)
        zh_TW.po (r1.6 -> r1.7)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/po/zh_TW.po.diff?r1=1.6&r2=1.7)
    pgsql-server/src/backend/utils/init:
        globals.c (r1.91 -> r1.92)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/utils/init/globals.c.diff?r1=1.91&r2=1.92)
    pgsql-server/src/backend/utils/misc:
        guc.c (r1.226 -> r1.227)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/utils/misc/guc.c.diff?r1=1.226&r2=1.227)
        postgresql.conf.sample (r1.119 -> r1.120)

(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/utils/misc/postgresql.conf.sample.diff?r1=1.119&r2=1.120)
    pgsql-server/src/include:
        miscadmin.h (r1.164 -> r1.165)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/include/miscadmin.h.diff?r1=1.164&r2=1.165)