Reverting part of the FIPS change

Only the very latest version of the S3 tool has the region tips computation. As such any older loads of the library will fail to operate.

Author: dljvette

lib/instance_agent/plugins/codedeploy/command_executor.rb

@@ -288,8 +288,11 @@ def s3_options
             options[:endpoint] = URI(InstanceAgent::Config.config[:s3_endpoint_override])
           elsif InstanceAgent::Config.config[:use_fips_mode]
             ProcessManager::Log.info("using fips endpoint")
-            # This is not a true region but a way to signal to the S3 client that a FIPS enpoint should be used; added in SDK3.
-            options[:region] = "fips-#{region}"
+            # There was a recent change to S3 client to decompose the region and use a FIPS endpoint is "fips-" is appended
+            # to the region. However, this is such a recent change that we cannot rely on the latest version of the SDK to be loaded.
+            # For now, the endpoint will be set directly if FIPS is active but can switch to the S3 method once we have broader support.
+            # options[:region] = "fips-#{region}"
+            options[:endpoint] = "https://s3-fips.#{region}.amazonaws.com"
           end
           proxy_uri = nil
           if InstanceAgent::Config.config[:proxy_uri]

test/instance_agent/plugins/codedeploy/command_executor_test.rb

@@ -353,8 +353,8 @@ def generate_signed_message_for(map)
               InstanceAgent::Config.config[:use_fips_mode] = true
             end
             should "use correct region and custom endpoint" do
-              assert_equal 'fips-us-east-1', @command_executor.s3_options[:region]
-              assert_false @command_executor.s3_options.include? :endpoint
+              assert_equal 'us-east-1', @command_executor.s3_options[:region]
+              assert_true @command_executor.s3_options.include? :endpoint
             end
           end      
         end