datatypes: Fix comment for the _virNetwork struct

The comment was copied form the domain and the object type was not
changed.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

src/datatypes.h

@@ -610,7 +610,7 @@ struct _virDomain {
 /**
 * _virNetwork:
 *
-* Internal structure associated to a domain
+* Internal structure associated to a network
 */
 struct _virNetwork {
     virObject parent;