Move saveStream and putBlob near blobCacheDestination.PutBlob
Move saveStream and putBlob near blobCacheDestination.PutBlob

This does not change a single line of the two functions, committed
separately to make reviews of actual changes easier.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

Closes: #1218
Approved by: rhatdan

rhatdan/buildah,rhatdan/buildah,nalind/buildah-1,projectatomic/buildah,projectatomic/buildah,TomSweeneyRedHat/buildah,nalind/buildah-1,nalind/buildah-1,ipbabble/buildah,projectatomic/buildah,nalind/buildah,nalind/buildah,ipbabble/buildah,TomSweeneyRedHat/buildah,TomSweeneyRedHat/buildah,rhatdan/buildah