Always update dom0 dnf.conf even if it is deleted

Also drop yum. It is not used anymore

Author: alimirjamali

dom0-updates/patch-dnf-yum-config

@@ -70,16 +70,10 @@ EOF
 
 ### helper functions end
 
-if [ -e /etc/dnf/dnf.conf ]; then
-    update_conf /etc/dnf/dnf.conf "
-reposdir=/etc/yum.real.repos.d
-installonlypkgs = kernel, kernel-qubes-vm"
-fi
+# If user deleted dnf.conf, create an empty one. Otherwise next step fails
+[ ! -f /etc/dnf/dnf.conf ]; touch /etc/dnf/dnf.conf
 
-if [ -e /etc/yum.conf ]; then
-    update_conf /etc/yum.conf "
+update_conf /etc/dnf/dnf.conf "
 reposdir=/etc/yum.real.repos.d
-installonlypkgs = kernel, kernel-qubes-vm
-distroverpkg = qubes-release"
-fi
+installonlypkgs = kernel, kernel-qubes-vm"