main/postmarketos-ui-xfce4: remove post-deinstall file
postmarketos-ui-xfce4.post-deinstall is an unnecessary file, because apk autoremoves this custom config file from lightdm. So, let's remove it.
We have discussed it here, so I've made a MR for it now:
!2106 (merged)
!2106 (comment 548853112)
Edited by Administrator