exec: Remove debugging fprintf() that slipped into qemu_ram_alloc_from_ptr()

Remove the debugging fprintf() slipped in via the following commit:

    commit b2e0a138
    Author: Michael S. Tsirkin <mst@redhat.com>
    Date:   Mon Nov 22 19:52:34 2010 +0200

        migration: stable ram block ordering

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>