When running golint on test/e2e/e2e.go, the following erros
were faced:

 $ golint e2e.go
 e2e.go:329:2: var metricsJson should be metricsJSON
 e2e.go:342:1: comment on exported function RunE2ETests should be of the
form "RunE2ETests ..."

This PR fixes them.