Take out HTTP_X_NOKIA_IPADDRESS

This short cut causes some tethered desktop connections to falsely
report as mobile devices. Particularly the EE network in the UK. It's
unfortunate to have to remove it, but a user agent check should cover
devices that this shortcut header anyway.
Merge pull request #229 from sheldon/HTTP_X_NOKIA_IPADDRESS

Take out HTTP_X_NOKIA_IPADDRESS