clean /var/lib/apt/lists/auxfiles so that apt older than 1.6 has no problem with the chroot

coverage.sh

@@ -155,6 +155,7 @@ grep -v '^Priority: ' /tmp/debian-$dist-mm/var/lib/dpkg/status > status2
 diff -u status1 status2
 rm status1 status2
 rm /tmp/debian-$dist-debootstrap/var/lib/dpkg/status /tmp/debian-$dist-mm/var/lib/dpkg/status
+# this file is only created by apt 1.6 or newer
 rmdir /tmp/debian-$dist-mm/var/lib/apt/lists/auxfiles
 # debootstrap exposes the hosts's kernel version
 rm /tmp/debian-$dist-debootstrap/etc/apt/apt.conf.d/01autoremove-kernels \

mmdebstrap

@@ -1641,6 +1641,11 @@ sub setup {
 
     # clean up temporary configuration file
     unlink "$options->{root}/etc/apt/apt.conf.d/00mmdebstrap" or error "failed to unlink /etc/apt/apt.conf.d/00mmdebstrap: $!";
+    # apt since 1.6 creates the auxfiles directory. If apt inside the chroot
+    # is older than that, then it will not know how to clean it.
+    if (-e "$options->{root}/var/lib/apt/lists/auxfiles") {
+	rmdir "$options->{root}/var/lib/apt/lists/auxfiles" or die "cannot rmdir /var/lib/apt/lists/auxfiles: $!";
+    }
 
     info "cleaning package lists and apt cache...";
     run_apt_progress({