NoMethodError: undefined method `start_with?' for nil:NilClass

[maia]

On rare occasions a redirected url does not seem to have a response['location'], causing the following:

> LinkThumbnailer.generate("http://www.egms.de/de/journals/mbi")
NoMethodError: undefined method `start_with?' for nil:NilClass
.../link_thumbnailer-3.0.2/lib/link_thumbnailer/processor.rb:73:in `resolve_relative_url'
.../link_thumbnailer-3.0.2/lib/link_thumbnailer/processor.rb:63:in `perform_request'
.../link_thumbnailer-3.0.2/lib/link_thumbnailer/processor.rb:27:in `block in call'
.../link_thumbnailer-3.0.2/lib/link_thumbnailer/processor.rb:35:in `with_valid_url'
.../link_thumbnailer-3.0.2/lib/link_thumbnailer/processor.rb:24:in `call'
.../link_thumbnailer-3.0.2/lib/link_thumbnailer/processor.rb:62:in `perform_request'
.../link_thumbnailer-3.0.2/lib/link_thumbnailer/processor.rb:27:in `block in call'
.../link_thumbnailer-3.0.2/lib/link_thumbnailer/processor.rb:35:in `with_valid_url'
.../link_thumbnailer-3.0.2/lib/link_thumbnailer/processor.rb:24:in `call'
.../link_thumbnailer-3.0.2/lib/link_thumbnailer/page.rb:17:in `generate'
.../link_thumbnailer-3.0.2/lib/link_thumbnailer.rb:16:in `generate'

[maia]

Thanks!