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
SERVER-15287 LiteParsedQuery should take ownership of request params

(cherry picked from commit 2ca7cef6b39d1ffc0c8b54ca6e12bb9d8c633060)
SERVER-13104 enumerate all possibilties for $or below an $and

(cherry picked from commit aac8ba84d8fac7dc531a03c63224fdfc8cd3baa3)
SERVER-15360 Make sure user cache is invalidated on 2.6 secondaries replicating from a 2.4 primary
SERVER-15319 Handle 2.8-style freelist bit in pdfile version
SERVER-15369 Explicitly write zeros when creating ns files
(cherry picked from commit 60d379f9e0c3eaf85850e768328d94c49170a7d7)

Conflicts:
	src/mongo/db/structure/catalog/namespace_index.cpp
BUMP 2.6.5-rc2