Use regex instead of string matching to support redirect correctly when path_style is set to true

- Before this change a user would get an exception because the case statement
would attempt to do the else case which would get an `undefined method captures for nil class`
because the region is acutally a default region

Signed-off-by: Aakash Shah <ashah@pivotal.io>

lib/fog/aws/storage.rb

@@ -606,7 +606,7 @@ module Fog
           Fog::Logger.warning("fog: followed redirect to #{host}, connecting to the matching region will be more performant")
           original_region, original_signer = @region, @signer
           @region = @new_region || case new_params[:host]
-          when 's3.amazonaws.com', 's3-external-1.amazonaws.com'
+          when /s3.amazonaws.com/, /s3-external-1.amazonaws.com/
             DEFAULT_REGION
           else
             %r{s3[\.\-]([^\.]*).amazonaws.com}.match(new_params[:host]).captures.first