In Train kolla switched to Python 3 in Debian and Ubuntu source images. For services running under httpd with mod_wsgi, they should install libapache2-mod-wsgi-py3 rather than libapache2-mod-wsgi. This was done for most images, but cyborg and monasca were omitted. This change fixes that. Change-Id: I25cfa62dbf20490685617b4a4185bf95ab91725e Closes-Bug: #1873421