SERVER-16499 Fix sh.getBalancerLockDetails

sh.getBalancerLockDetails was returning state instead of the whole lock object

Closes #873

Signed-off-by: Matt Kangas <matt.kangas@mongodb.com>
SERVER-16508 Add tests for mixed version/storage engine replica sets.

Closes #879

Signed-off-by: Matt Kangas <matt.kangas@mongodb.com>
SERVER-16111 improve style
Merge remote-tracking branch 'upstream/master'