By default, grub2-mkconfig scans everything to look for other
environments and then load those into the grub configuration.
It makes sense, but on newer versions of grub2 in distribution
images, os-prober is taking an exceptionally long time in some
cases where more than one storage device exists with other
filesystems.
As a result, of the os-prober execution by grub2-mkconfig, the
bootloader installation can completely time out and fail the
deployment. This is presently experienced with metalsmith on
centos8.
There are numerous sporatic reports of issues like this issue
where grub2-mkconfig hangs for some period of time, and this is
observable on Centos8.2 in our CI. While one report[0] mentions
this issue, Another bug [1] has the dialog that actually helps us
frame the context as to what we likely should do.
Also, fixes the unit testing so we actually test if we're running
with grub2. :\
[0]: https://bugzilla.redhat.com/show_bug.cgi?id=1744693
[1]: https://bugzilla.redhat.com/show_bug.cgi?id=1709682
Depends-On: https://review.opendev.org/#/c/748315
Change-Id: I14bf299afef3a1ddb2006fe5f182d7f0d249e734
6542a9cb04