tsm: screen: fix cell-initialization on line resize

We didn't correctly initialize new lines on resize. In fact, we didn't
initialize new cells at all. This was all covered by a nasty-fix in the
screen-resize handler.
This fixes the line-resize handler to initialize all new cells correctly.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

src/tsm_screen.c

@@ -160,7 +160,6 @@ static int line_resize(struct tsm_screen *con, struct line *line,
 			return -ENOMEM;
 
 		line->cells = tmp;
-		line->size = width;
 
 		while (line->size < width) {
 			cell_init(con, &line->cells[line->size]);