Lock down the grafana required version to 4.5.2
Lock down the grafana required version to 4.5.2

The latest version available in grafana repo does not works
as expected with tendrl. This patch will lock down the
grafana version to 4.5.2

tendrl-bugid: Tendrl/monitoring-integration#224
Signed-off-by: Timothy Asir J <9ae03c403dd2d82025ba1aad4fc83885ac926861@redhat.com>

Tendrl/monitoring-integration