force headers to be str in flask response for login

Without explicity forcing the response headers to be str types, I get 500 a error (logs show aTypeError: expected byte string object for header name, value of type unicode found)  when attempting to use the login view/page with apache/mod_wsgi.  Each time you declare a string in the login view it becomes a unicode string, I'm guessing this is a werkzeug/flask thing, but I must admit, I don't really know why this happens.