Update test_data2passcal.py - add unit tests to mock ftp connection failure, and rename environment variable MOCK_TEST to SEND4REAL; Update tox.ini to pass environment variables to test commands

Update data2passcal.py - replace logger.error by logger.exception, add exception for socket.gethostname(), and rename test.dat; Update test_data2passcal.py - use data2passcal timeout constants, and set MOCK_TEST as an environment variable

Specify timeouts for unit tests; Clean up imports and try/excepts in data2passcal.py; Recreate test.dat under ftp://ftp.passcal.nmt.edu/download/public/

Update test_data2passcal.py - remove setup() and rethink test_scan_dir(); Update .gitlab-ci.yml - remove call to tox