This change whitelists the supported filesystems which can be set
as Default FS for Impala to run on.
This patch configures Impala to use S3 as the default filesystem, rather
than a secondary filesystem as before.
Change-Id: I2f45bef6c94ece634045acb906d12591587ccfed
Reviewed-on: http://gerrit.cloudera.org:8080/1121
Reviewed-by: anujphadke <aphadke@cloudera.com>
Tested-by: Internal Jenkins