[core] coerce service credentials

lib/fog/core/service.rb

@@ -56,6 +56,7 @@ module Fog
         end
 
         validate_options(options)
+        coerce_options(options)
         setup_requirements
 
         if Fog.mocking?
@@ -114,6 +115,24 @@ module Fog
         @collections ||= []
       end
 
+      def coerce_options(options)
+        options.each do |key, value|
+          value_string = value.to_s.downcase
+          if value == value_string.to_i.to_s
+            options[key] = value.to_i
+          else
+            options[key] = case value_string
+            when 'false'
+              false
+            when 'true'
+              true
+            else
+              value
+            end
+          end
+        end
+      end
+
       def mocked_requests
         @mocked_requests ||= []
       end