[aws|auto_scaling] mark describe_*_types requests as idempotent

lib/fog/aws/requests/auto_scaling/describe_adjustment_types.rb

@@ -24,6 +24,7 @@ module Fog
         def describe_adjustment_types()
           request({
             'Action'    => 'DescribeAdjustmentTypes',
+            :idempotent => true,
             :parser     => Fog::Parsers::AWS::AutoScaling::DescribeAdjustmentTypes.new
           })
         end

lib/fog/aws/requests/auto_scaling/describe_auto_scaling_notification_types.rb

@@ -24,6 +24,7 @@ module Fog
         def describe_auto_scaling_notification_types()
           request({
             'Action'    => 'DescribeAutoScalingNotificationTypes',
+            :idempotent => true,
             :parser     => Fog::Parsers::AWS::AutoScaling::DescribeAutoScalingNotificationTypes.new
           })
         end

lib/fog/aws/requests/auto_scaling/describe_metric_collection_types.rb

@@ -26,6 +26,7 @@ module Fog
         def describe_metric_collection_types()
           request({
             'Action'    => 'DescribeMetricCollectionTypes',
+            :idempotent => true,
             :parser     => Fog::Parsers::AWS::AutoScaling::DescribeMetricCollectionTypes.new
           })
         end

lib/fog/aws/requests/auto_scaling/describe_scaling_process_types.rb

@@ -25,6 +25,7 @@ module Fog
         def describe_scaling_process_types()
           request({
             'Action'    => 'DescribeScalingProcessTypes',
+            :idempotent => true,
             :parser     => Fog::Parsers::AWS::AutoScaling::DescribeScalingProcessTypes.new
           })
         end

lib/fog/aws/requests/auto_scaling/describe_termination_policy_types.rb

@@ -23,6 +23,7 @@ module Fog
         def describe_termination_policy_types()
           request({
             'Action'    => 'DescribeTerminationPolicyTypes',
+            :idempotent => true,
             :parser     => Fog::Parsers::AWS::AutoScaling::DescribeTerminationPolicyTypes.new
           })
         end