Fixed event-mon credentials file name
Fixed event-mon credentials file name

To match the file name used by the deployment system.

BUG=471433

Review URL: https://codereview.chromium.org/1115863002

nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra