Catch an IOError that happens on Ruby 2.0

Would get a #<IOError: closed stream> error when running in my MRI 2.0 environment (works fine on 1.9.3). Either there's a Ruby change in the `net/http` works or something else in the `guard-livereload` server (I'm using an old 1.0.3 here), but this looks to work for me.