Kill redundant redundant null checks

I caught one during a review and figured I might as well sweep the whole
tree, so this patch was created using Coccinelle and the following steps:

    $ cat >check_obj.cocci <<EOF
    @@
    expression obj, magic;
    @@

    if (obj != NULL) {
    - CHECK_OBJ_NOTNULL(obj, magic);
    + CHECK_OBJ(obj, magic);
    ...
    }
    EOF
    $ spatch --dir . --in-place --sp-file check_obj.cocci

This is my fourth semantic patch, I wouldn't mind checking them in to
have them handy in the repo to semi-automate code polish every now and
then. For example in a /tools/cocci directory. This way people could
study them or use them in their out-of-tree projects like VMODs or VUTs.

bin/varnishd/cache/cache_deliver_proc.c

@@ -127,7 +127,7 @@ VDP_close(struct req *req)
 		if (vdc->retval >= 0)
 			AN(vdpe);
 		if (vdpe != NULL) {
-			CHECK_OBJ_NOTNULL(vdpe, VDP_ENTRY_MAGIC);
+			CHECK_OBJ(vdpe, VDP_ENTRY_MAGIC);
 			VTAILQ_REMOVE(&vdc->vdp, vdpe, list);
 			if (vdpe->vdp->fini != NULL)
 				AZ(vdpe->vdp->fini(req, &vdpe->priv));

bin/varnishd/cache/cache_vrt_var.c

@@ -503,7 +503,7 @@ VRT_u_bereq_body(VRT_CTX)
 	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
 	CHECK_OBJ_NOTNULL(ctx->bo, BUSYOBJ_MAGIC);
 	if (ctx->bo->req != NULL) {
-		CHECK_OBJ_NOTNULL(ctx->bo->req, REQ_MAGIC);
+		CHECK_OBJ(ctx->bo->req, REQ_MAGIC);
 		ctx->bo->req = NULL;
 		ObjSetState(ctx->bo->wrk,
 		    ctx->bo->fetch_objcore, BOS_REQ_DONE);

bin/varnishd/cache/cache_vrt_vcl.c

@@ -436,7 +436,7 @@ vcl_call_method(struct worker *wrk, struct req *req, struct busyobj *bo,
 	CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
 	INIT_OBJ(&ctx, VRT_CTX_MAGIC);
 	if (req != NULL) {
-		CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
+		CHECK_OBJ(req, REQ_MAGIC);
 		CHECK_OBJ_NOTNULL(req->sp, SESS_MAGIC);
 		CHECK_OBJ_NOTNULL(req->vcl, VCL_MAGIC);
 		VCL_Req2Ctx(&ctx, req);

lib/libvarnish/vev.c

@@ -413,7 +413,7 @@ VEV_Once(struct vev_root *evb)
 	tmo = INFTIM;
 	e = binheap_root(evb->binheap);
 	if (e != NULL) {
-		CHECK_OBJ_NOTNULL(e, VEV_MAGIC);
+		CHECK_OBJ(e, VEV_MAGIC);
 		assert(e->__binheap_idx == BINHEAP_NOIDX + 1);
 		t = VTIM_mono();
 		if (e->__when <= t)

lib/libvarnishapi/vxp_parse.c

@@ -629,7 +629,7 @@ vex_print(const struct vex *vex, int indent)
 
 	fprintf(stderr, "%*s%s", indent, "", vxp_tnames[vex->tok]);
 	if (vex->lhs != NULL) {
-		CHECK_OBJ_NOTNULL(vex->lhs, VEX_LHS_MAGIC);
+		CHECK_OBJ(vex->lhs, VEX_LHS_MAGIC);
 		AN(vex->lhs->tags);
 		fprintf(stderr, " lhs=");
 		if (vex->lhs->level >= 0)

lib/libvmod_directors/vmod_shard.c

@@ -402,7 +402,7 @@ shard_get_key(VRT_CTX, const struct vmod_directors_shard_param *p)
 	switch (p->by) {
 	case BY_HASH:
 		if (ctx->bo) {
-			CHECK_OBJ_NOTNULL(ctx->bo, BUSYOBJ_MAGIC);
+			CHECK_OBJ(ctx->bo, BUSYOBJ_MAGIC);
 			return (vbe32dec(ctx->bo->digest));
 		}
 		/* FALLTHROUGH */