Upgrade to ruby 2.1.2 and remove old build patch
Use the new built in command for compiling passenger native support
Don't use cache on some builds and remove intermediate containers on success
Install common-deps earlier in the process and cache the first build step

The purpose of this change is to pull in all the needed disto files as early
as possible as they do not need to be pulled in each time a new ruby is built.
Show stdout and stderr when building
Factor out username for the index
Push images to index after build