fix vips-properties.xml

and we're done

TODO

@@ -1,13 +1,3 @@
-- verify xml data against master for vips save and dzsave
-
-- curious
-
-	$ vips tiffload_buffer images/sample.tif 
-	(vips:18224): GLib-GObject-WARNING **: unable to set property 'buffer' of type 'VipsBlob' from value of type 'gchararray'
-	Trace/breakpoint trap (core dumped)
-
-
-
 - vips linecache has access there twice!
 
 	 $ vips linecache

libvips/iofuncs/vips.c

@@ -861,7 +861,6 @@ vips__xml_properties_meta( VipsImage *image,
 			return( dbuf );
 		}
 		str = vips_value_get_save_string( &save_value );
-		g_value_unset( &save_value );
 
 		vips_dbuf_writef( dbuf, "    <property>\n" );  
 		vips_dbuf_writef( dbuf, "      <name>" ); 
@@ -872,6 +871,8 @@ vips__xml_properties_meta( VipsImage *image,
 		dbuf_write_amp( dbuf, str );
 		vips_dbuf_writef( dbuf, "</value>\n" ); 
 		vips_dbuf_writef( dbuf, "    </property>\n" );  
+
+		g_value_unset( &save_value );
 	}
 
 	return( NULL );