Fixed a bug -- to_a is going away, lots of warning messages when spec…

…s are run.

Signed-off-by: Ezra Zygmuntowicz <ez@engineyard.com>

merb_helpers/lib/merb_helpers/form_helpers.rb

@@ -451,7 +451,7 @@ def options_for_select(collection, attrs = {})
             end
           else
             collection.each do |value,text|
-              options = selected.to_a.include?(value) ? {:selected => 'selected'} : {}
+              options = Array(selected).include?(value) ? {:selected => 'selected'} : {}
               ret << tag( 'option', text, {:value => value}.merge(options) )
             end
           end