Description of problem:

The aarch64 Fedora 21 image uses EFI and therefore has a
FAT partition mounted under /boot/efi.  Trying to use
the virt-builder --upload option fails:

$ touch /tmp/test
$ virt-builder --arch aarch64 fedora-21 \
  --upload /tmp/test:/boot/efi/test
[...]
virt-builder: error: libguestfs error: chown: /boot/efi/test: 1000.1000: 
Operation not permitted

Enabling trace shows that we're running chmod + chown (why?)

libguestfs: trace: chmod 420 "/boot/efi/test"
libguestfs: trace: chmod = 0
libguestfs: trace: chown 1000 1000 "/boot/efi/test"
libguestfs: trace: chown = -1 (error)

It should probably detect if the mountpoint is FAT and
avoid the chown at least.

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

virt-builder 1.29.24

How reproducible:

100%