Add a test that check that init connect only once. It fails.
* __init__.py: (test_suite): Register the new test class.
* test_init.py: (InstrumentedTransport): A transport that can track connections. (TransportHooks): Transport specific hooks. (TestInit): Iniit command behavior tests.
* ftp.py: (FtpTransport.__init__): Mark place that need fixing regarding transport connection sharing
* builtins.py: (cmd_init.run): Mark places that need fixing regarding transport connection sharing.