benchmarks: add set -o pipefail
benchmarks: add set -o pipefail

It seems that our automated benchmarks job was failing to build for the
last several days, but we didn't notice because it didn't use
'pipefail'. Thus the 'make | tee build.log' failure didn't actually
cause the script to exit with a bad status code, and we kept running the
binaries from a previous revision.

Change-Id: I6ab66e85cf39c6513da61e472c85e34da77205fc
Reviewed-on: http://gerrit.cloudera.org:8080/7123
Reviewed-by: Alexey Serbin <864f6b82bd94e8dda64141d4274519ee66e0102e@cloudera.com>
Reviewed-by: Adar Dembo <866ca730bfc7f544e3ebce604ceeba4879f23df0@cloudera.com>
Tested-by: Todd Lipcon <2c763d726a8c2f6afda9be7e0e56a2caa6bb5e6b@apache.org>

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