[master] cb91e43 modernize just enough

[Nils Goroll]

commit cb91e43a944183887f2cdab6bb93ca1abc4977a3
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Wed Dec 7 12:12:37 2016 +0100

    modernize just enough

diff --git a/tools/vtest.sh b/tools/vtest.sh
index befc44f..312c08e 100755
--- a/tools/vtest.sh
+++ b/tools/vtest.sh
@@ -130,7 +130,7 @@ i=0
 
 while [ $MAXRUNS -eq 0 ] || [ $i -lt $MAXRUNS ]
 do
-	i=`expr $i + 1`
+	i=$((i + 1))
 
 	(cd varnish-cache && git pull > /dev/null 2>&1 || true)
 	rev=`cd varnish-cache && git show -s --pretty=format:%H`