commands/mkinitramfs.py: Set config.busybox

When creating the initramfs, busybox is needed, so search for it in the
root filesystem.

Suggested-by: Andy Lutomirsky <luto@kernel.org>
Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
diff --git a/virtme/commands/mkinitramfs.py b/virtme/commands/mkinitramfs.py
index 48a2af8..b7c602e 100755
--- a/virtme/commands/mkinitramfs.py
+++ b/virtme/commands/mkinitramfs.py
@@ -27,6 +27,9 @@
         config.modfiles = modfinder.find_modules_from_install(
             virtmods.MODALIASES, kver=args.mod_kversion)
 
+    # search for busybox in the root filesystem
+    config.busybox = mkinitramfs.find_busybox(root = '/', is_native = True)
+
     if args.rw:
         config.access = 'rw'