SERVER-15279 disable hash-based index intersection by default

(cherry picked from commit 5e2b3c29b438f936eeb0a675e70e0131ab4c145a)

Conflicts:
	src/mongo/dbtests/plan_ranking.cpp
SERVER-14168 Don't logOp drop of "inc" collection in MR

The creation and inserts into it are not logOp'd so logging the drop lead to
a warning being printed on secondaries.

(cherry picked from commit 69e509c06de65ae0cd49805841e3d6018ac6e6bc)
SERVER-15087 check for dropped collection in MR

(cherry picked from commit aa5c0a136c9ab37023d89908c8b02d6d687ed070)
SERVER-15087 Get owned copy of document in MR final reduce

(cherry picked from commit 92bf7260c3dda79abf9f6b2bdf9e7fb827f6743a)
SERVER-15111 Treat corruption of final journal section as an expected event

Manual backport of the following commits (combined):
8e1f5beabfad09c790e46826e8b3c7dcc5070d8d
6e93b33179e71abce820e534b3d32f1e593f71ca
SERVER-13702 Commands without optional query may target to wrong shards on mongos

(cherry picked from commit bd1a02385378ee50a33db7c255217c050cc74192)

SERVER-13702 Add JS tests for shard targeting.

(cherry picked from commit e986b037f1301fae63938dc9bd933ff8ac25b7d6)
SERVER-14887 Remove user document validation from the storage layer.

User documents are validated in the user management commands, validating them in the storage layer
makes the system less flexible and causes problems with mixed-version replica sets.
SERVER-15286 don't try to explode for sort if zero fields to explode

(cherry picked from commit 55415503b722848d51fe45fc2de2d47cee4db952)
SERVER-15152 refactor IXSCAN stage to avoid doing too much in one work() cycle
SERVER-14981 don't generate cell ids > coarsestIndexedLevel when building covering

(cherry picked from commit 6e90ddf91fdbbc578e499fcb736365498e47f55a)

Conflicts:
	src/mongo/db/query/expression_index.cpp
SERVER-11077 Debian Enterprise packaging

(cherry picked from commit 82feb98aae3d44b7c6e9a6843ea60d3b49d92692)
SERVER-14023 Add RHEL 7 Enterprise .rpm

(cherry picked from commit 5181c39ebe970ef8053c70e7c283510d8ed2f41a)
SERVER-13243 Add Ubuntu 14.04 Enterprise .deb

(cherry picked from commit 097039445a16436ee0e992b1613c7b0b6b269a2d)
SERVER-14964 collect debug stats for find and update if log level is greater than zero
SERVER-15287 Can't use index key pattern plugin fields to provide sort

(cherry picked from commit ad1dafb013342faae7e998586a0c35b70ba75636)
BUMP 2.6.5-rc0
post 2.6.5-rc0
SERVER-15319 Forward-compatible change for 2.8 freelist

Makes NamespaceDetails::orphanDeletedList() also orphan the new 2.8-only
deleted lists. This ensures that 2.8 won't attempt to reuse the space in
extents that no longer belong to this collection.
BUMP 2.6.5-rc1
post 2.6.5-rc1