pgsql: Rename PM_RECOVERY_CONSISTENT and PMSIGNAL_RECOVERY_CONSISTENT.

Log Message:
-----------
Rename PM_RECOVERY_CONSISTENT and PMSIGNAL_RECOVERY_CONSISTENT.

The new names PM_HOT_STANDBY and PMSIGNAL_BEGIN_HOT_STANDBY more accurately
reflect their actual function.

Modified Files:
--------------
    pgsql/src/backend/access/transam:
        xlog.c (r1.412 -> r1.413)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xlog.c?r1=1.412&r2=1.413)
    pgsql/src/backend/postmaster:
        postmaster.c (r1.607 -> r1.608)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/postmaster.c?r1=1.607&r2=1.608)
    pgsql/src/include/storage:
        pmsignal.h (r1.30 -> r1.31)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/pmsignal.h?r1=1.30&r2=1.31)