Description of problem: It should be possible to do: virt-builder --touch /.autorelabel fedora-21 Version-Release number of selected component (if applicable): libguestfs-1.29.36-1.fc23.x86_64
A workaround for creating empty files is: virt-builder --write /.autorelabel: but that isn't exactly the same as what the touch command does.
Fixed with https://github.com/libguestfs/libguestfs/commit/22686d2cfd1793a4f2baa477650445fe2b5b4524