SERVER-15763 Report issecondary:true while newly elected primary drains unapplied oplog entries.

Such nodes already report ismaster:false, so need to report issecondary:true to
indicate that they are ready to accept reads.
SERVER-15771 Ignore the RefusesToStand unelectable reason when responding to a node's fresh check.

If a node sent out a replSetFresh command, it must consider itself electable, so
there's no point in telling it that it doesn't think itself electable.  It only
happens because the fresh request arrived before the next relevant heartbeat
response.
SERVER-15733 disable test
SERVER-15711: revert changes to flush lock ordering an increase buffer size
BUMP 2.7.8
Merge remote-tracking branch 'upstream/master' into kv_dictionary