IMPALA-2883: increase cluster kill timeout
IMPALA-2883: increase cluster kill timeout

We saw some random failures when cluster processes took longer than 10 seconds
to shut down.

Change-Id: I63de8834c47faae1b3406e7129214ce74e777c92
Reviewed-on: http://gerrit.cloudera.org:8080/1888
Reviewed-by: Alex Behm <fe1626037acfc2dc542d2aa723a6d14f2464a20c@cloudera.com>
Tested-by: Internal Jenkins

ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC