Description of problem:
GiB changes to B for the Disk size field, in Edit boot source reference modal, when editing VM Template's boot source reference.

Version-Release number of selected component (if applicable):
4.11

How reproducible:
always

Steps to Reproduce:
1. Go to VM Template list
2. For some template, choose Edit boot source reference - Actions column
3. In the modal, edit Disk size field: click into the field and try to write any char (does not matter if number or not) or delete the default value that is 30.

Actual results:
The unit GiB disappears, then 0 B appears, no matter the user writes in the field.

Expected results:
The unit GiB stays displayed and the value can be edited normally.

Additional info: