Fix test to keep behavior the same after rails#48397

This test was failing because the parameter `a` in the accept header
is now being correctly extracted as a mime type.

This test was expecting that Rails would extract it an an empty accept
header, that will only happen now if the `q` parameter that has special
meaning in used.

Author: rafaelfranca

actionview/test/actionpack/controller/render_test.rb

@@ -1083,7 +1083,7 @@ def test_should_render_formatted_html_erb_template
   end
 
   def test_should_render_formatted_html_erb_template_with_bad_accepts_header
-    @request.env["HTTP_ACCEPT"] = "; a=dsf"
+    @request.env["HTTP_ACCEPT"] = "; q=dsf"
     get :formatted_xml_erb
     assert_equal "<test>passed formatted HTML erb</test>", @response.body
   end