IMPALA-12930: Fix TestExtDataSources.test_jdbc_data_source failure

The patch of IMPALA-12802 added some negative test cases for altering
external JDBC table. These test cases verify the error messages.
One of test cases failed on some test environments due to different
error message returned from Postgres server.

This patch fixes the unit-test failure by checking if the error message
is matching with one of two possible error messages.

Testing:
 - Ran the unit-test on Jenkins with centos and ubuntu and verified the
   unit-test passed for different error messages.

Change-Id: I84566f67751538d72a4d17da21e7ea907e1dcdd2
Reviewed-on: http://gerrit.cloudera.org:8080/21181
Reviewed-by: Wenzhe Zhou <wzhou@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
diff --git a/testdata/workloads/functional-query/queries/QueryTest/jdbc-data-source.test b/testdata/workloads/functional-query/queries/QueryTest/jdbc-data-source.test
index 72e375b..8f74016 100644
--- a/testdata/workloads/functional-query/queries/QueryTest/jdbc-data-source.test
+++ b/testdata/workloads/functional-query/queries/QueryTest/jdbc-data-source.test
@@ -481,7 +481,7 @@
 ---- QUERY
 select * from jdbc_test order by id limit 5;
 ---- CATCH
-row_regex:.*Caught exception.*(FATAL: password authentication failed for user "UNKNOWN")
+row_regex:.*(FATAL: password authentication failed for user "UNKNOWN"|FATAL: role "UNKNOWN" does not exist).*
 ====
 ---- QUERY
 # Alter JDBC table to set correct username and password.