Always update uefi boot entry in bootconfig

[linnemannr_gmail.com]

Summary

Change 40923b0c81cc introduced a conditional check on BSDINSTALL_CONFIGCURRENT
to control whether or not to run efibootmgr to add and activate and entry for
the loader installed to the destination ESP. This prevents diskless scripted
installers from installing a bootable system where the EFI boot entry does not
already exist.

This change removes the conditional on BSDINSTALL_CONFIGCURRENT, so that on a
diskless installer the boot entry is added and activated as expected.

[jrtc27]

This makes sense to me, FWIW. The poorly-named BSDINSTALL_CONFIGCURRENT is supposed to be about whether or not to configure the current system’s network to match what is being configured for the installed system. Normally you do them both at the same time, but for diskless/netbooted you want to keep your existing network connection during the installer. Having it also affect whether you call efibootmgr (whilst still modifying the ESP!) like it does today really doesn’t make sense.

[imp]

In addition to what's been said, this won't affect other installation scenarios adversely that I can tell.