Don't reuse GCS cache in imagebuilder

[jlewi]

Here we don't rebuild the context on GCS if it already exists

hydros/pkg/images/controller.go

Line 158 in 7987df4

// TODO(jeremy): It might be better to delete the GCSPath if it exists and then recreate it. This way if the logic

Therefore if there is a bug in how the context is computed and we push a fix to hydros the context won't get recomputed. An example of that is a bug like #69.

It might be better to delete the object after some amount of time and recereate it.