SERVER-14607 fix compile for index intersection dbtest
SERVER-14431 Invalid chunk data after splitting on a key that's too large to index
(cherry picked from commit 0e8a436fdedc9a56ddd4e773d45d7963a8f358a6)
(cherry picked from commit 7174d92cc1ad3dd24430769b72c05b1ee6fbcd74)
(cherry picked from commit 4f01ffd9cbbb0dcb4ee2f9167ad2337178259ba9)
SERVER-14123 prevent explain BSON from growing too large on mongos

(cherry picked from commit ffc53f46956eb52a86efd51620dede98e1b48444)
Merge remote-tracking branch 'upstream/v2.6' into v2.6