Remove duplicated logic from FromUrlLoader

Library/Homebrew/formulary.rb

@@ -143,23 +143,10 @@ class Formulary
       super formula, HOMEBREW_CACHE_FORMULA/File.basename(uri.path)
     end
 
-    # Downloads the formula's .rb file
-    def fetch
-      begin
-        have_klass = Formulary.formula_class_defined? class_name
-      rescue NameError
-        raise FormulaUnavailableError.new(name)
-      end
-
-      unless have_klass
-        HOMEBREW_CACHE_FORMULA.mkpath
-        FileUtils.rm path.to_s, :force => true
-        curl url, '-o', path.to_s
-      end
-    end
-
-    def get_formula(spec)
-      fetch
+    def load_file
+      HOMEBREW_CACHE_FORMULA.mkpath
+      FileUtils.rm_f(path)
+      curl url, "-o", path
       super
     end
   end