use readPref method to allow reads from secondaries

Author: kay-kim

source/applications/replication.txt

@@ -223,10 +223,10 @@ replica set as in the following setting:
    information about replica set reconfiguration and tag sets.
 
 .. index:: read preference
-.. index:: slaveOk
+
 
 .. _replica-set-read-preference:
-.. _slaveOk:
+
 .. _read-preference:
 
 Read Preference

source/reference/javascript.txt

@@ -188,7 +188,6 @@ Replica Set Methods
 - :method:`db.isMaster()`
 - :method:`db.printReplicationInfo()`
 - :method:`db.printSlaveReplicationInfo()`
-- :method:`mongo.setSlaveOk()`
 - :method:`rs.add()`
 - :method:`rs.addArb()`
 - :method:`rs.conf()`
@@ -197,7 +196,6 @@ Replica Set Methods
 - :method:`rs.initiate()`
 - :method:`rs.reconfig()`
 - :method:`rs.remove()`
-- :method:`rs.slaveOk()`
 - :method:`rs.status()`
 - :method:`rs.stepDown()`
 - :method:`rs.syncFrom()`

source/reference/method/mongo.setSlaveOk.txt

@@ -60,9 +60,6 @@ methods, see :doc:`/reference/method`.
 .. include:: /reference/method/rs.remove.txt
    :start-after: mongodb
 
-.. include:: /reference/method/rs.slaveOk.txt
-   :start-after: mongodb
-
 .. include:: /reference/method/db.isMaster.txt
    :start-after: mongodb