BUG/MINOR: htx: Remove a forgotten while loop in htx_defrag()

Fortunately, this loop does nothing. Otherwise it would have led to an infinite
loop. It was probably forgotten during a refactoring, in the early stage of the
HTX.

This patch must be backported to 1.9.
diff --git a/src/htx.c b/src/htx.c
index 525f7ef..9deddb1 100644
--- a/src/htx.c
+++ b/src/htx.c
@@ -64,7 +64,7 @@
 		new++;
 		addr += blksz;
 
-	} while (new < htx->used);
+	}
 
 	htx->sl_off = sl_off;
 	htx->wrap = htx->used;