we should first allow super AbstractAdapter to initialize then extend spec

otherwise using *adapter: jdbc* configuration might no work (fixes #457)

Author: kares

lib/arjdbc/jdbc/adapter.rb

@@ -64,14 +64,15 @@ def initialize(connection, logger, config = nil)
         @config[:adapter_spec] = adapter_spec(@config) unless @config.key?(:adapter_spec)
         spec = @config[:adapter_spec]
 
-        # kind of like `extend ArJdbc::MyDB if self.class == JdbcAdapter` :
-        klass = @config[:adapter_class]
-        extend spec if spec && ( ! klass || klass == JdbcAdapter)
         # NOTE: adapter spec's init_connection only called if instantiated here :
         connection ||= jdbc_connection_class(spec).new(@config, self)
 
         super(connection, logger)
 
+        # kind of like `extend ArJdbc::MyDB if self.class == JdbcAdapter` :
+        klass = @config[:adapter_class]
+        extend spec if spec && ( ! klass || klass == JdbcAdapter)
+
         # NOTE: should not be necessary for JNDI due reconnect! on checkout :
         configure_connection if respond_to?(:configure_connection)