Revert "IMPALA-1760: Implement shutdown command"

This reverts commit fda44aed9d.

A couple of the tests broken on S3 and erasure coding. Reverting
to unblock testing until we can come up with a proper fix.

Change-Id: Icef47b3aa67bc056c40592d47e93c4ebc57be98c
Reviewed-on: http://gerrit.cloudera.org:8080/11435
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Reviewed-by: Tim Armstrong <tarmstrong@cloudera.com>

common/thrift/generate_error_codes.py

@@ -363,7 +363,6 @@ error_codes = (
   ("SCRATCH_READ_VERIFY_FAILED", 118, "Error reading $0 bytes from scratch file '$1' "
    "on backend $2 at offset $3: verification of read data failed."),
 
-  ("SERVER_SHUTTING_DOWN", 119, "Server is being shut down: $0."),
 )
 
 import sys