Adjust imports in tests to new path

tests/test_main.py

@@ -10,7 +10,7 @@ from freqtrade.configuration import Arguments
 from freqtrade.freqtradebot import FreqtradeBot
 from freqtrade.main import main
 from freqtrade.state import State
-from freqtrade.tests.conftest import (log_has, patch_exchange,
+from tests.conftest import (log_has, patch_exchange,
                                       patched_configuration_load_config_file)
 from freqtrade.worker import Worker