My commit 0c1d863 broke formatting of passthrough smartcard devices:
<smartcard mode='passthrough' type='spicevmc'/>
resulted in invalid XML:
<smartcard mode='passthrough'>
type='spicevmc'>
<address type='ccid' controller='0' slot='0'/>
</smartcard>
Split out chardev source formatting function into two -
one formatting the attributes and other formatting the subelements.
Reported-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
