Drop default retry count to 1

This is enough to enable basic recovery for everyone by default, while
leaving more time-consuming repeated attempts for those who configure
them.

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -166,7 +166,7 @@ def use_metadata_table?
       end
 
       def connection_retries
-        (@config[:connection_retries] || 3).to_i
+        (@config[:connection_retries] || 1).to_i
       end
 
       def default_timezone