[6.0] 069ccecbc Drop VALID_OBJ for GCC

[Dridi Boukelmoune]

commit 069ccecbcef4567cd52f228fb5113b36661fbd92
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Wed May 2 11:53:53 2018 +0200

    Drop VALID_OBJ for GCC
    
    It complains that &pfh_vut is never NULL...

diff --git a/lib/libvarnishapi/vut.c b/lib/libvarnishapi/vut.c
index a793e44a6..a34243b61 100644
--- a/lib/libvarnishapi/vut.c
+++ b/lib/libvarnishapi/vut.c
@@ -77,7 +77,7 @@ static void
 vut_vpf_remove(void)
 {
 
-	assert(VALID_OBJ(&pfh_vut, VUT_MAGIC));
+	assert(pfh_vut.magic == VUT_MAGIC);
 	AN(pfh);
 	AN(pfh_vut.P_arg);