Pin gnocchi plugin version
Pin gnocchi plugin version

The repo added support for grafana3; however this breaks our image build
due to changed filenames.

Change-Id: I8415278869dbae9bfc41d608b96b2c0ba7c5880e

enovance/software-factory,enovance/software-factory,enovance/software-factory,enovance/software-factory,enovance/software-factory