[master] c938f4d create the tests directory before the automake generated wrapper races for it

[Nils Goroll]

commit c938f4d7565c716f32d56d216983f7f52452eb9e
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Thu Dec 8 16:45:35 2016 +0100

    create the tests directory before the automake generated wrapper races for it
    
    am__check_pre in the automake-generated Makefile basically runs
    
    	test -d tests || mkdir tests || exit $?
    
    When running out-of-tree with parallel make (as vtest does), this
    becomes racy. Avoid the race by a mkdir ignoring the error

diff --git a/bin/varnishtest/Makefile.am b/bin/varnishtest/Makefile.am
index 1da5b60..1d5696f 100644
--- a/bin/varnishtest/Makefile.am
+++ b/bin/varnishtest/Makefile.am
@@ -9,6 +9,7 @@ check: check-am check-local
 check-am: check-local
 # See if list of checks have changed, recheck
 check-local:
+	mkdir tests 2>/dev/null || true ; \
 	LC_ALL=C; \
 	if [ "$$(cd $(srcdir) && echo tests/*.vtc)" != "@VTC_TESTS@" ]; then \
 		cd $(top_builddir) && ./config.status --recheck ; \