[rackspace|storage] remove nil query params in requests

lib/fog/storage/requests/rackspace/get_container.rb

@@ -29,6 +29,7 @@ module Fog
         #       * 'last_modified'<~String> - Last modified timestamp
         #       * 'name'<~String> - Name of object
         def get_container(container, options = {})
+          options.reject! {|key, value| value.nil?}
           response = request(
             :expects  => 200,
             :method   => 'GET',

lib/fog/storage/requests/rackspace/get_containers.rb

@@ -18,6 +18,7 @@ module Fog
         #       * 'count'<~Integer>: - Number of items in container
         #       * 'name'<~String>: - Name of container
         def get_containers(options = {})
+          options.reject! {|key, value| value.nil?}
           response = request(
             :expects  => [200, 204],
             :method   => 'GET',