KUDU-2802: C++ tableExists API optimizations
KUDU-2802: C++ tableExists API optimizations

Change-Id: Ie3a7c325adf464d0932d84001de6753079f64ee6
Reviewed-on: http://gerrit.cloudera.org:8080/13443
Reviewed-by: Adar Dembo <866ca730bfc7f544e3ebce604ceeba4879f23df0@cloudera.com>
Tested-by: Adar Dembo <866ca730bfc7f544e3ebce604ceeba4879f23df0@cloudera.com>

helifu/kudu,helifu/kudu,helifu/kudu,helifu/kudu,helifu/kudu,helifu/kudu,helifu/kudu,helifu/kudu,helifu/kudu