get_image_info: Use 'bytes' value from qemu-img instead of normalize_data_size value

Don't use the 'normalize_data_size()' method for the returned 'vsize'.
Use the 'bytes' value within the parentheses since it's the real value
that qemu-img finds/determines from the meta data.

Signed-off-by: John Ferlan <jferlan@redhat.com>