+++ This bug was initially created as a clone of Bug #954691 +++

When attempting to customize btrfs mount options and subvolumes during the
installation, partitioner just reverts to defaults after saving the changes.

As explained in the original bug, there are actually 2 bugs:

 (A) - For fstab options, it always "forgets" the settings

 (B) - For subvolumes and "enable snapshots" it fails in a similar way for the
root (/) partition, but correctly remember the settings for other Btrfs
partitions (let's say /home)

Let's use this bug report to track (B).