Fix actionmailer patches to correctly handle absolute paths.

Newer versions of Rails 2.3.x, like 2.3.10, changed #template_path to
return absolute paths for plugin views -- previously these were always
relative. This change broke plugins like exception
notifiers which contain their own mailer templates. This fix simply checks
whether the paths are absolute and only modifies them if they're relative.

lib/patches/actionmailer_ex.rb

@@ -24,8 +24,12 @@ def create!(method_name, *parameters) #:nodoc:
         theme_template_roots[path] = ActionView::Base.process_view_paths(File.dirname(path)).first
       end
 
-      tpaths << File.join(RAILS_ROOT, template_path)
-      theme_template_roots[File.join(RAILS_ROOT, template_path)] = template_root
+      absolute_template_path =
+        Pathname.new(template_path).absolute? ?
+          template_path :
+          File.join(RAILS_ROOT, template_path)
+      tpaths << absolute_template_path
+      theme_template_roots[absolute_template_path] = template_root
 
       # If an explicit, textual body has not been set, we check assumptions.
       unless String === @body
@@ -88,4 +92,4 @@ def create!(method_name, *parameters) #:nodoc:
       @mail = create_mail
     end
   end
-end
+end