Adds conflict checking to the sysctl-write-value script
to detect settings from multiple elements conflicting.
Change-Id: If312d199388036d6f4103e94dca99249cb3bcbaf
Theres a pretty standard workflow for setting a sysctl value which will
be applied on image boot which was written by tripleo. Lets move this in
tree as other folks (like Octavia) would like to depend on it.
Change-Id: I3c266870d417cdba3196f5fa65c4cd634ab13173