SERVER-14184 Remove unused S2 macros that conflict on OS X Yosemite

(cherry picked from commit 759b6e8cabfb745b712b5ffd0748561129c3b421)
SERVER-15673 Disable SSLv3 ciphers (CVE-2014-3566 "POODLE")

(cherry picked from commit bdee10aed8691579d17300a1235edce8742ef6dd)
SERVER-15580 KeepMutationsStage shouldn't deref invalidated iterator

(cherry picked from commit e1ef3e6371f59c6a6396e78b2a4c4d9a975e9396)