Memory allocated with GLib needs to be freed with GLib.  Freeing it
with free() instead of g_free() is a common error.  Harmless when
g_free() is a trivial wrapper around free(), which is commonly the
case.  But model the difference anyway.

In a local scan, this flags four ALLOC_FREE_MISMATCH.  Requires
--enable ALLOC_FREE_MISMATCH, because the checker is still preview.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>