pip-and-virtualenv : fix fedora 30 install

This should be installing the python2 and python3 packages (that's
what pip-and-virtualenv is designed to do), but we dropped the +=
accidentally in ee9ad32b6f.

However, we've moved on anyway and after
I7a6a342461d6001c25e55638ba9b7438c28f2519 F31 doesn't support this
element.  fedora-latest is already updated to f31 in the opendev gate.
Remove the testing as it is no longer relevant.

Change-Id: Id696a90baa1eb05cb4c08501f8dac3665d395682

.zuul.d/jobs.yaml

@@ -95,7 +95,6 @@
       # These can only build on bionic
       dib_functests_extra:
         - fedora-minimal/build-succeeds
-        - pip-and-virtualenv/source-install-fedora
     voting: false
 
 - job:

diskimage_builder/elements/pip-and-virtualenv/install.d/pip-and-virtualenv-source-install/04-install-pip

@@ -30,8 +30,8 @@ if [[ $DISTRO_NAME =~ (opensuse|fedora|centos|centos7|rhel|rhel7) ]]; then
             ;;
         fedora)
             _do_py3=1
-            packages="python2-virtualenv python2-pip python2-setuptools"
+            packages="python2-pip python2-setuptools"
-            packages=" python3-virtualenv python3-pip python3-setuptools"
+            packages+=" python3-virtualenv python3-pip python3-setuptools"
             ;;
         rhel)
             case "$DIB_RELEASE" in