Firefox is ignoring `en-us` language selection

[dshuffma-ibm]

Going to any of the samples w/Firefox and its showing me Japanese instead of english.

https://console.stage1.bluemix.net/devops/setup/deploy/?repository=https%3A//github.com/open-toolchain/simple-toolchain&env_id=ibm:ys1:us-south

Looking at my language selection order (in Firefox):

If I add en to the list, its all resolved. Bust most of the Bluemix services I've seen don't require this and will take en-us.