Fix expected types for exhaustive compute stats results

Change-Id: Idaffa50b5d023bb912eb7e3717133fe0a9bbc825
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2901
Reviewed-by: Marcel Kornacker <marcel@cloudera.com>
Tested-by: jenkins
IMPALA-827: Follow-on comments

Change-Id: Ibb5deb972517871191d1cc89b499b1eb4fd47f7b
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2158
Reviewed-by: Henry Robinson <henry@cloudera.com>
Tested-by: jenkins