A float was being passed in for "Instances Logical Volume Size" and the
form field is an integer. The field was hidden on image backing edits
and thus the user could not see the error.
Closes-Bug: 1791998
Change-Id: Ia1f34845a5c01d269c511f707a7f1022ec461a35
Signed-off-by: Kristine Bujold <kristine.bujold@windriver.com>