Reduce `tox -e lint` verbosity
Reduce `tox -e lint` verbosity

Closes #1161

vongazman/libcloud,apache/libcloud,StackPointCloud/libcloud,andrewsomething/libcloud,vongazman/libcloud,apache/libcloud,Kami/libcloud,mistio/libcloud,Scalr/libcloud,vongazman/libcloud,pquentin/libcloud,Kami/libcloud,Scalr/libcloud,andrewsomething/libcloud,pquentin/libcloud,ByteInternet/libcloud,mistio/libcloud,ByteInternet/libcloud,ByteInternet/libcloud,Scalr/libcloud,Kami/libcloud,StackPointCloud/libcloud,StackPointCloud/libcloud,mistio/libcloud,apache/libcloud,pquentin/libcloud,andrewsomething/libcloud