correctly revert to SharedCredentials over ECSCredentials

Signed-off-by: Joshua Atkins <[email protected]>

Author: atkinsj

lib/fluent/plugin/in_s3.rb

@@ -218,7 +218,7 @@ def setup_credentials
         c = @shared_credentials
         credentials_options[:path] = c.path if c.path
         credentials_options[:profile_name] = c.profile_name if c.profile_name
-        options[:credentials] = Aws::ECSCredentials.new(credentials_options)
+        options[:credentials] = Aws::SharedCredentials.new(credentials_options)
       else
         # Use default credentials
         # See http://docs.aws.amazon.com/sdkforruby/api/Aws/S3/Client.html