Fix operators in UEFI post-install load check
&! is not a thing, and os-autoinst has been warning us about
this forever:
Use of uninitialized value in bitwise and (&) at fedora/main.pm line 310.
I just sorta didn't notice. Apparently this turned out to work,
but it wasn't *right*. Let's do it this way instead.
Signed-off-by: Adam Williamson <awilliam@redhat.com>