Fix a typo introduced in revision 4272


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4276 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/exec.c b/exec.c
index c556de0..d9e959d 100644
--- a/exec.c
+++ b/exec.c
@@ -2557,7 +2557,7 @@
                 /* FIXME - should this return an error rather than just fail? */
                 return;
             memcpy(buf, p, l);
-            unlock_user(p, addr, l);
+            unlock_user(p, addr, 0);
         }
         len -= l;
         buf += l;