This reverts commit b5490d8a98.
When resizing a volume of a running VM, a qmp block_resize command
is issued. This is non-blocking, so the size on the storage immediately
after issuing the command might still be the old one.
This is part of the issue reported in bug #2621.
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>