Encode headers and params
    
    BaseClient currently fails when non-ascii characters are passed in
    paramas and headers. This patch ensures those params are correctly
    encoded before the request is made.
    
    The patch adds strutils from oslo and updates gettextutils.
    
    Fixes bug: #1182824
    
    Change-Id: I813d745d76700c77f1871b151a76ff8b72ea92d4