Switch dbconsole config loader check

In a three-tier config environment
`configurations[environment].presence` will return `{ :primary => {
:key => value, :key => value }, :secondary => { :key => value, :key =>
value} }, which means it's not given a single config to connect to.

If we flip these however it will connect to primary because that's the
default connection, and on a two tier it will be `nil` so the code will
select the connection from the configurations rather than the
connection.

railties/lib/rails/commands/dbconsole/dbconsole_command.rb

@@ -97,7 +97,7 @@ module Rails
         elsif configurations[environment].blank? && configurations[connection].blank?
           raise ActiveRecord::AdapterNotSpecified, "'#{environment}' database is not configured. Available configuration: #{configurations.inspect}"
         else
-          configurations[environment].presence || configurations[connection]
+          configurations[connection] || configurations[environment].presence
         end
       end
     end