Community Edition 4.2.6-rc12 Release Candidate 12

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge remote-tracking branch 'origin/candidate-4.2.6' into closedown-4.2.x

Conflicts:
	version.cmake

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>