SERVER-13760 Do not call dateToISOString if date is not formatable
(cherry picked from commit 99fa4e6058a24d6c4d7fde19ce940719c5bbc210)
SERVER-10462 retry file deletes until the file is no longer being used by another process in testing on windows

(cherry picked from commit f9be10eccac4ce39ad64d84bd02916257f9a8ef6)
SERVER-13960 fix access planning for OR with inexact child predicates

Includes a refactor of QueryPlannerAccess::processIndexScans(...) which makes this
change saner.

(cherry picked from commit bee249ac8907cc9de6b19ba87c3fcb074d84b1a3)
SERVER-13960 bug fixes for OR with inexact predicates

(cherry picked from commit 3242afb803a5cc523f16c2c63c3ee1dfc10a5671)
SERVER-13865 handle edge case for v2.4 when upserted _id not returned

(cherry picked from commit 090ea9a5ad1ed52e40b5a66df5ee1eab283845cb)
SERVER-14082: freelist scan does not short circuit in MaxBucket
BUMP 2.6.2-rc0
post 2.6.2-rc0
Merge remote-tracking branch 'upstream/v2.6' into v2.6