updated merge instructions

hosts/frontend.bbb.tbm.tudelft.nl/updating.md

@@ -55,7 +55,13 @@ git merge upstream-2.9.0
 
 Update the branch adding streaming:
 ```
-git checkout tud streaming
+git checkout streaming
+git merge upstream-2.9.0
+```
+
+Update the branch removing avartars:
+```
+git checkout disable_avatar
 git merge upstream-2.9.0
 ```
 
@@ -67,6 +73,7 @@ git merge rec_restrictions
 git merge openid-changes
 git merge tud_visual
 git merge streaming
+git merge disable_avatar
 ```
 
 Push the new custom branch to github