client_samples-test: respect TEST_TMPDIR
client_samples-test: respect TEST_TMPDIR

Otherwise we might end up putting data in a location not intended by a
Jenkins job.

Change-Id: I1ca7263040f837ec973f6e98dbae2274a00377fe
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/6753
Reviewed-by: Todd Lipcon <2c763d726a8c2f6afda9be7e0e56a2caa6bb5e6b@cloudera.com>
Tested-by: Adar Dembo <866ca730bfc7f544e3ebce604ceeba4879f23df0@cloudera.com>

cloudera/kudu,cloudera/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,EvilMcJerkface/kudu,andrwng/kudu,andrwng/kudu,helifu/kudu,EvilMcJerkface/kudu,helifu/kudu,helifu/kudu,helifu/kudu,InspurUSA/kudu,cloudera/kudu,helifu/kudu,helifu/kudu,InspurUSA/kudu,andrwng/kudu,andrwng/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,InspurUSA/kudu,InspurUSA/kudu,cloudera/kudu,helifu/kudu,EvilMcJerkface/kudu,andrwng/kudu,andrwng/kudu,andrwng/kudu,cloudera/kudu,InspurUSA/kudu,helifu/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,andrwng/kudu,EvilMcJerkface/kudu,andrwng/kudu,cloudera/kudu,cloudera/kudu,cloudera/kudu,EvilMcJerkface/kudu,cloudera/kudu,helifu/kudu,InspurUSA/kudu