Fix pip install command

The --user option does not solicit a value, so this was previously attempting to install a package sharing a name with the current user.

Author: jmikola

.travis.yml

@@ -77,7 +77,7 @@ matrix:
 
 before_install:
   - openssl aes-256-cbc -K $encrypted_b354efda2943_key -iv $encrypted_b354efda2943_iv -in .travis.scripts/atlas-uris.txt.enc -out .travis.scripts/atlas-uris.txt -d || true
-  - pip install "mongo-orchestration>=0.6.7,<1.0" --user `whoami`
+  - pip install --user "mongo-orchestration>=0.6.7,<1.0"
   - .travis.scripts/before_install.sh
   - export SERVER_FILENAME=mongodb-linux-x86_64-${SERVER_DISTRO}-${SERVER_VERSION}
   - wget -qO- http://fastdl.mongodb.org/linux/${SERVER_FILENAME}.tgz | tar xz