Added code to force 'flavor' arguments to str.
Added code to force 'flavor' arguments to str.

opsdisk/pyrax,ddaeschler/pyrax,pratikmallya/pyrax,briancurtin/pyrax,mandx/pyrax,sivel/pyrax,0dataloss/pyrax,naemono/pyrax,EdLeafe/pyrax,roelvv/pyrax,rackerlabs/heat-pyrax,rackspace/pyrax,vikomall/pyrax