Install python-ironicclient in /usr/local

This is where python3.9 has been installed
Fixes: #609

resources/ironic-client/Dockerfile

@@ -8,7 +8,7 @@ COPY scripts/openstack /usr/bin/openstack
 RUN apt-get update && \
     apt-get install -y genisoimage && \
     apt-get clean && \
-    pip3 install --prefix /usr --no-cache-dir python-ironicclient && \
+    pip3 install --prefix /usr/local --no-cache-dir python-ironicclient && \
     chmod +x /usr/bin/openstack
 
 ENTRYPOINT ["/usr/bin/baremetal"]