remove quotes

Author: pipermerriam

.travis.yml

@@ -19,7 +19,7 @@ install:
   - travis_retry pip install tox
   - travis_retry pip install coverage
 script:
-  - if [ -d ".tox/$TOX_ENV/" ]; then cd ".tox/$TOX_ENV" && coverage erase"; fi;
+  - if [ -d .tox/$TOX_ENV/ ]; then cd .tox/$TOX_ENV && coverage erase"; fi;
   - tox -e $TOX_ENV -- --ignore ethereum/tests/test_vm.py --ignore ethereum/tests/test_state.py
   - tox -e $TOX_ENV -- ethereum/tests/test_vm.py
   - tox -e $TOX_ENV -- ethereum/tests/test_state.py