Don't install scripts straight to /usr/local/bin

This results in more then just the openstack clients getting installed
to /usr/local/bin. In my case /usr/local/bin/pip was part of the
python-novaclient virtualenv and being used globally. Instead link to
what we want inside the virtualenv.

Change-Id: If44b397cdd80c46bf5a2a86d7369a4d74e09b58c

elements/openstack-clients/install.d/51-openstack-clients

@@ -27,7 +27,8 @@ for client in $client_install_list; do
     elif [ -e tools/pip-requires ]; then
         pip install -r tools/pip-requires
     fi
-    python setup.py develop --script-dir /usr/local/bin
+    python setup.py develop
+    ln -s /opt/stack/venvs/$repo/bin/$client /usr/local/bin/$client
     popd
 
     set +u