Added some missing docstrings.
Added some missing docstrings.

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