sync with ep-engine/command_ids.h

Change-Id: Ic244016a84557aa11115ef44b6e37a5ad344c24e
Reviewed-on: http://review.couchbase.org/30781
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>