Fix SHOW DATA SOURCE test; must execute setup/cleanup serially

The SHOW DATA SOURCE tests were run as part of the other SHOW * tests
in test_show(), but the setup/cleanup for data sources can't be run
in parallel. This change moves the SHOW DATA SOURCE tests into a separate
test method and the setup/cleanup code is only run for this test (i.e.
not using setup_method() and teardown_method()). The test is then
only executed serially.

Change-Id: I221145f49cfe7290e132c6a87a5295b747c1fcc7
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2864
Reviewed-by: Matthew Jacobs <mj@cloudera.com>
Tested-by: jenkins
IMPALA-788: Loading an HBase table when HBase/Zookeeper are unavailable takes a long time to fail

This is because the default HBase/Zookeeper client timeouts are meant to be very long:

* If both Zookeeper and HBase are down, it will wait:
  hbase.client.retries.number(default 10) x hbase.rpc.timeout (default 60s)
* If ZK is up but HBase is down, but it has run at least once, then it waits:
  hbase.client.retries.number * some exponential backoff time (default sleep time is 1 second,
  backoff tables looks like this: 1, 1, 1, 2, 2, 4, 4, 8, 16, 32, 64).

In my experiments, it takes ~20-25minutes if HBase before the table loading will fail. If there
are many HBase tables this can block all loading threads.

The fix is to change the default timeout values to fail faster. These values were suggested
by somoene from the HBase team. With these values we will fail in ~1 minute. I am working with the CM team to get the defaults changed there as well.

Change-Id: I625e35af57374c72d50d03372d177624ce67694a
Reviewed-on: http://gerrit.ent.cloudera.com:8080/1903
Reviewed-by: Nong Li <nong@cloudera.com>
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Tested-by: Lenni Kuff <lskuff@cloudera.com>
IMPALA-943: removed database udf_test from front-end tests

Added CATCH section to test files.

Change-Id: I28ba3a6e5ae4c53df5b86505573793d7b150863b
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2782
Reviewed-by: Victor Bittorf <victor.bittorf@cloudera.com>
Tested-by: jenkins