Workaround Travis CI dpl dependency issue

Author: zhaoqin-github

.travis.yml

@@ -33,7 +33,11 @@ after_success:
   - md5sum ${PKG_RELEASE_EL7} > ${PKG_RELEASE_EL7}.md5 && md5sum --check ${PKG_RELEASE_EL7}.md5
   - md5sum ${PKG_RELEASE_1404} > ${PKG_RELEASE_1404}.md5 && md5sum --check ${PKG_RELEASE_1404}.md5
 
-before_deploy: PKG_VERSION=$(python -c "import f5; print(f5.__version__)")
+before_deploy:
+  - PKG_VERSION=$(python -c "import f5; print(f5.__version__)")
+  # Workaround https://github.com/travis-ci/dpl/issues/1235
+  - python3 -m venv ~/venv
+  - source ~/venv/bin/activate
 deploy:
   - provider: pypi
     user: $PYPI_USER