[travis] remove multiprocessing

doesn't install :(

.travis.yml

@@ -13,7 +13,7 @@ install:
   - pip install codeclimate-test-reporter
   - pip install i3-py Pillow Babel DateTime python-dateutil
   - pip install docker feedparser i3ipc
-  - pip install multiprocessing netifaces power
+  - pip install netifaces power
   - pip install psutil pygit2 pytz random
   - pip install requests simplejson
   - pip install socket speedtest suntime