IMPALA-6711: loosen shell test prompt regex
IMPALA-6711: loosen shell test prompt regex

We have seen this test fail because the fully-qualified domain name
differed between the python test process and the impala shell process
(see JIRA for details). The exact domain name is irrelevant to the test
- we only really care about whether the prompt appeared or not.

Change-Id: I24078ef97d56e5bb32fd866af861e3a1d19c8c44
Reviewed-on: http://gerrit.cloudera.org:8080/9831
Reviewed-by: Tim Armstrong <2f8e34250f03a653da3dc27f7ec203eafdde80fc@cloudera.com>
Tested-by: Impala Public Jenkins <039b6b20426ff68ebe492b3021890d8c8fd010c9@cloudera.com>

cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala