Using the bitbake recipe you can build an ipk and install using opkg; assuming you have a bitbake mlinux environment available.
Otherwise, you could follow the build from source instructions: http://www.eclipse.org/paho/clients/python/
As git is not on the conduit you would have to clone to your desktop and then transfer to the conduit or download the latest copy on github as a tarball/zip ( https://github.com/eclipse/paho.mqtt.python/archive/master.zip ). Then you can cd into the directory and run ‘python setup.py install’