RTD requirements fix #8.

requirements.txt

@@ -10,24 +10,12 @@ ethtool==0.14
 MarkupSafe==0.23
 pycairo==1.16.3
 pycparser==2.14
-pycups==1.9.72
-pycurl==7.43.0.2
-pydbus==0.6.0
 pyenchant==2.0.0
-pygobject==3.28.3
-pyinotify==0.9.6
-pykickstart==3.16.10
 pyOpenSSL==18.0.0
 pyparsing==2.1.10
 pyparted==3.11.0
-PySocks==1.6.8
 python-dateutil==2.6.1
-python-dmidecode==3.12.2
-python-linux-procfs==0.6
-python-meh==0.47.2
 pytz==2017.2
-pyudev==0.21.0
-pyxdg==0.25
 PyYAML==3.12
 requests==2.20.0
 requests-file==1.4.3