IMPALA-2865: Disable show create table test on S3
IMPALA-2865: Disable show create table test on S3

Change http://gerrit.cloudera.org:8080/1740 introduced a test that uses
"create table as select" and afterwards verifies the output of "show
create table". This kind of test does not work on S3 and as its tests
otherwise only target metadata we disable test_show_create_table.py on
S3.

Change-Id: I2f82872d28a2bf50cac53b1a87379a5fb20c1e18
Reviewed-on: http://gerrit.cloudera.org:8080/1822
Tested-by: Internal Jenkins
Reviewed-by: Alex Behm <fe1626037acfc2dc542d2aa723a6d14f2464a20c@cloudera.com>

ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC