Make it the third option

Because it doesn't make sense to source /etc/cdmrc before the one in
$XDG_CONFIG_HOME

src/cdm

@@ -65,10 +65,10 @@ if [[ -n "$1" ]]; then
     fi
 elif [[ -f "$HOME/.cdmrc" ]]; then
     source "$HOME/.cdmrc"
-elif [[ -f /etc/cdmrc ]]; then
-    source /etc/cdmrc
 elif [[ -f "$XDG_CONFIG_HOME/cdm/cdmrc" ]]; then
     source "$XDG_CONFIG_HOME/cdm/cdmrc"
+elif [[ -f /etc/cdmrc ]]; then
+    source /etc/cdmrc
 fi
 
 # Default options.