We need to check exception name to be nil

In Ruby 2.0 Exception leaves the name as nil

See below example.

```ruby                                                                                                                                               
2.0.0p195 :001 > begin
2.0.0p195 :002 >     Object.const_get('::')
2.0.0p195 :003?>   rescue => e
2.0.0p195 :004?>   puts e.name
2.0.0p195 :005?>   end

 => nil

ruby-1.9.3-p429
1.9.3p429 :001 > begin
1.9.3p429 :002 >     Object.const_get('::')
1.9.3p429 :003?>   rescue => e
1.9.3p429 :004?>   puts e.name
1.9.3p429 :005?>   end
::
 => nil
```

This will fix build broke by #10943 for ruby-2.0