Revert "storage/reflink: update volume size in __init__()"
Revert "storage/reflink: update volume size in __init__()"

Fixed more generally in one of the next commits ("storage/reflink:
preferably get volume size from image size").

This reverts commit 9f5d05bfde04746e8d47972b306c924bad080c60.

marmarek/qubes-core-admin,QubesOS/qubes-core-admin,marmarek/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,QubesOS/qubes-core-admin