Catch all Pygments errors

An unrecognized language was generating a MentosError rather than a
PythonError. Just catch anything that goes wrong in Pygments.

lib/gollum/markup.rb

@@ -558,12 +558,12 @@ module Gollum
         encoding ||= 'utf-8'
         begin
           hl_code = Pygments.highlight(code, :lexer => lang, :options => {:encoding => encoding.to_s})
-        rescue ::RubyPython::PythonError
+        rescue
           hl_code = code
         end
         highlighted << hl_code
       end
-      
+
       @codemap.each do |id, spec|
         body = spec[:output] || begin
           if (body = highlighted.shift.to_s).size > 0

test/test_markup.rb

@@ -534,6 +534,14 @@ np.array([[2,2],[1,3]],np.float)
     assert_equal %Q{<p>a\n</p><div class=\"highlight\"><pre><span class=\"nt\">&lt;p&gt;</span>a\n!rel<span class=\"nt\">&lt;/p&gt;</span>\n</pre></div>\n}, output
   end
 
+  test "code block in unsupported language" do
+    @wiki.write_page("a", :markdown, "a\n```nonexistent\ncode\n```\nb", commit_details)
+
+    page = @wiki.page("a")
+    output = page.formatted_data
+    assert_equal %Q{<p>a\ncode\nb</p>}, output
+  end
+
   #########################################################################
   #
   # Web Sequence Diagrams