nsinit is broken/disabled

[jbeda]

Starting with #1532 it is totally busted.

We are no longer building components on the target machines so if we want to re-add this we'll have to build it like the rest of our binary components.

[jbeda]

Time -- I don't have a lot of context of where this stuff is going. If nsinit should be built as a precompiled binary with the rest of everything I can do that if you give me guidance on how to build it.

[thockin]

I think we should punt and fall back on docker exec. This will break the existing gcutil functionality, but it's already broken.