Move container entrypoint to tier 0

tier-1/user-experience.yaml

@@ -2,10 +2,6 @@
 # https://github.com/openshift/os/blob/71c974b1e456292033e3ef3fe7bcfe17d1855ebc/manifest.yaml#L12
 # Only apply changes here that should apply to both FCOS and RHCOS.
 
-# Default to `bash` in our container, the same as other containers we ship.
-container-cmd:
-  - /usr/bin/bash
-
 # These packages are either widely used utilities/services or
 # are targeted for improving the general CoreOS user experience.
 # It is intended to be kept generic so that it may be shared downstream with