Check that xmpp is installed before adding user

src/freedombone-adduser

@@ -178,12 +178,14 @@ chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/README
 chown $MY_USERNAME:$MY_USERNAME $MY_GPG_PUBLIC_KEY
 chmod 600 /home/$MY_USERNAME/README
 
-echo "Adding an XMPP account for $MY_USERNAME"
-freedombone-addxmpp -e "$MY_USERNAME@$HOSTNAME" -p "$NEW_USER_PASSWORD"
-if [ ! "$?" = "0" ]; then
-    echo "XMPP account not created"
-    userdel -r $MY_USERNAME
-    exit 8
+if grep -q "install_xmpp" $COMPLETION_FILE; then
+    echo "Adding an XMPP account for $MY_USERNAME"
+    freedombone-addxmpp -e "$MY_USERNAME@$HOSTNAME" -p "$NEW_USER_PASSWORD"
+    if [ ! "$?" = "0" ]; then
+        echo "XMPP account not created"
+        userdel -r $MY_USERNAME
+        exit 8
+    fi
 fi
 
 if grep -q "Blog domain" $COMPLETION_FILE; then