.travis: Change mysql driver

Author: ashcrow

.travis.yml

@@ -7,7 +7,7 @@ services:
 before_script:
   - mysql -e 'create database track_usage_test;'
   - psql -c 'create database track_usage_test;' -U postgres
-  - pip install coverage pep8 pymongo==3.5.1 sqlalchemy psycopg2 mysql-python mongoengine
+  - pip install coverage pep8 pymongo==3.5.1 sqlalchemy psycopg2 mysqlclient mongoengine
 install:
   - pip install -e .
 script: