Revert "impala ec2-user"

This reverts commit 218cad09024ddc6495b6b5c9e971e0740c1ff34f.
Revert "fixed typo"

This reverts commit c3d87bf5de544a19c7d2aed4c7d3d0e5aa82a8c6.
Revert "changed impala benchmark import to support centos"

This reverts commit d9dbb416858c6e52d55b3c5856619650e6dd7458.