Allow symbol and string names to be passed through (deploy resource does the lookup dance automatically).

resources/default.rb

@@ -36,7 +36,7 @@ attribute :path, :kind_of => String
 attribute :owner, :kind_of => String
 attribute :group, :kind_of => String
 attribute :strategy, :kind_of => [String, Symbol], :default => :deploy_revision
-attribute :scm_provider, :kind_of => Class
+attribute :scm_provider, :kind_of => [Class, String, Symbol]
 attribute :revision, :kind_of => String
 attribute :repository, :kind_of => String
 attribute :environment, :kind_of => Hash, :default => {}