Update travis configuration

don't use "sudo pip install" in travis.yml

.travis.yml

@@ -21,7 +21,7 @@ install:
   - export PATH=${HOME}/maintainer-quality-tools/travis:${PATH}
   - travis_install_nightly
   - git clone https://github.com/OCA/connector ${HOME}/connector -b ${VERSION}
-  - sudo pip install cmislib
+  - pip install cmislib
 
 script:
   - travis_run_flake8