Move runCommand to util.go

Change-Id: I31f97eda61520962d8cfec8adc0176384cb5ad42
Use steno in container.go

Change-Id: I3ce1a51e3793bcb341e5fe4a8dc7157f5523f59c
Make sure tempfile is always closed

Change-Id: I46de8561197a92416fb50ff06f272db4a67f4a43
More logging

Change-Id: I4dc3953ce0d4a4b8052e1ed60c1a56066f72f248
Merge changes I4dc3953c,I46de8561,I3ce1a51e,I31f97eda into go

* changes:
  More logging
  Make sure tempfile is always closed
  Use steno in container.go
  Move runCommand to util.go