Add readline to the dependencies for Mac OSX
Add readline to the dependencies for Mac OSX

Some platforms i.e., Mac OSX don't support readline module in the
standard library. This patch adds the explicit dependency declaration to
setup.py to install readline module on the installation.

Signed-off-by: Taku Fukushima <48ddf7139da17a0278f1f27e611ac6b9304f94b2@midokura.com>

midokura/python-midonetclient,midonet/python-midonetclient,midonet/python-midonetclient,midokura/python-midonetclient