Changes to how the version string was handled created small regression with the release of consul 1.12.0 enterprise.
Many tools use the Config:Version field reported by the agent/self resource to determine whether Consul is an enterprise or OSS instance, expect something like 1.12.0+ent for enterprise and simply 1.12.0 for OSS. This was accidentally broken during the runup to 1.12.x
This work fixes the value returned by both the self endpoint in ["Config"]["Version"] and the metrics consul.version field.
Signed-off-by: Mark Anderson <manderson@hashicorp.com>