Change shell to print WARNINGS instead of ERRORS

Change-Id: I8b41a2f4307e31eda970ca891adb4f12fea926bb
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3088
Reviewed-by: Skye Wanderman-Milne <skye@cloudera.com>
Tested-by: Skye Wanderman-Milne <skye@cloudera.com>