[master] 1e1903483 vrt: Missing assertion

[Dridi Boukelmoune]

commit 1e1903483cb7ee601db4f859bd0d948d3f6da554
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Mon Aug 9 06:29:15 2021 +0200

    vrt: Missing assertion
    
    Spotted by flexelint.

diff --git a/bin/varnishd/cache/cache_vrt_re.c b/bin/varnishd/cache/cache_vrt_re.c
index 944a40bce..58d980d1b 100644
--- a/bin/varnishd/cache/cache_vrt_re.c
+++ b/bin/varnishd/cache/cache_vrt_re.c
@@ -76,7 +76,7 @@ VRT_re_match(VRT_CTX, const char *s, VCL_REGEX re)
 	if (i >= 0)
 		return (1);
 	if (i < VRE_ERROR_NOMATCH ) {
-		VSB_init(vsb, errbuf, sizeof errbuf);
+		AN(VSB_init(vsb, errbuf, sizeof errbuf));
 		AZ(VRE_error(vsb, i));
 		AZ(VSB_finish(vsb));
 		VSB_fini(vsb);