partially revert last commit(DefaultStrategy import IS needed).

* don't run functions in travis in a way we don't support

freqtrade/strategy/__init__.py

@@ -3,6 +3,8 @@ import sys
 from copy import deepcopy
 
 from freqtrade.strategy.interface import IStrategy
+# Import Default-Strategy to have hyperopt correctly resolve
+from freqtrade.strategy.default_strategy import DefaultStrategy  # noqa: F401
 
 
 logger = logging.getLogger(__name__)