BUG/MAJOR: trash must always be the size of a buffer

Before it was possible to resize the buffers using global.tune.bufsize,
the trash has always been the size of a buffer by design. Unfortunately,
the recent buffer sizing at runtime forgot to adjust the trash, resulting
in it being too short for content rewriting if buffers were enlarged from
the default value.

The bug was encountered in 1.4 so the fix must be backported there.
diff --git a/src/sock_raw.c b/src/sock_raw.c
index b7edbfc..db38cd5 100644
--- a/src/sock_raw.c
+++ b/src/sock_raw.c
@@ -529,7 +529,7 @@
 		 * (which is recomputed every time since it's constant). If
 		 * it is positive, it means we have to send from the start.
 		 */
-		ret = make_proxy_line(trash, sizeof(trash),
+		ret = make_proxy_line(trash, trashlen,
 				      &b->prod->addr.from, &b->prod->addr.to);
 		if (!ret)
 			return -1;