[master] 7a12b1c3f clarify first byte timeout FetchError message

[Nils Goroll]

commit 7a12b1c3ff670d83970b9299882b4808fe2ab5df
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Fri Nov 20 09:42:44 2020 +0100

    clarify first byte timeout FetchError message
    
    For a first byte timeout on a new connection, we emit
    
            FetchError: first byte timeout
    
    For a first byte timeout being reached on a recycled connection, we
    should keep the error message similar.
    
    Ref eecd409d13f145765de3aeee4984179e0ae008b5

diff --git a/bin/varnishd/cache/cache_backend.c b/bin/varnishd/cache/cache_backend.c
index f4a9aadc4..826ca94df 100644
--- a/bin/varnishd/cache/cache_backend.c
+++ b/bin/varnishd/cache/cache_backend.c
@@ -301,7 +301,7 @@ vbe_dir_gethdrs(VRT_CTX, VCL_BACKEND d)
 			    bo->htc->first_byte_timeout) != 0) {
 				bo->htc->doclose = SC_RX_TIMEOUT;
 				VSLb(bo->vsl, SLT_FetchError,
-				     "Timed out reusing backend connection");
+				     "first byte timeout (reused connection)");
 				extrachance = 0;
 			}
 		}