SERVER-13441 getUser and getRole shell helpers shouldn't throw when user/role not found
(cherry picked from commit abf252cfe8833ab15dc8d62e8e05a30108484508)
SERVER-13534 Remove data in test array_shard_key.js
(cherry picked from commit 122aaea7105a99a343c4e2b2934bb1cb731047b2)
Merge remote-tracking branch 'upstream/v2.6' into v2.6