Replace dstat with pcp-dstat
Replace dstat with pcp-dstat

The dstat project is no longer maintained.

The pcp-dstat package installs a dstat command so no further updates to
the scripts should be needed.

Change-Id: Ied8c9d29bed4f887c364db7080a0f2a0c02328af
Signed-off-by: Lucas Alvares Gomes <ef89b923b1145c9ec2fd96eee513279016a7a963@gmail.com>

openstack-dev/devstack,nawawi/openstack,nawawi/openstack,openstack-dev/devstack