middleware/chaos: fix version (#669)

* middleware/chaos: fix version

Move the version setting into a init function so it is done early. Then
tweak the setup code for chaos a bit to correctly pick this version up.
Add an integration test to pick this up in the toplevel test/ directory.

Fixes #667

* Update tests

middleware/chaos/setup_test.go

@@ -1,7 +1,6 @@
 package chaos
 
 import (
-	"fmt"
 	"strings"
 	"testing"
 
@@ -17,20 +16,12 @@ func TestSetupChaos(t *testing.T) {
 		expectedErrContent string // substring from the expected error. Empty for positive cases.
 	}{
 		// positive
-		{
-			`chaos`, false, defaultVersion, "", "",
-		},
 		{
 			`chaos v2`, false, "v2", "", "",
 		},
 		{
 			`chaos v3 "Miek Gieben"`, false, "v3", "Miek Gieben", "",
 		},
-		{
-			fmt.Sprintf(`chaos {
-				%s
-			}`, defaultVersion), false, defaultVersion, "", "",
-		},
 	}
 
 	for i, test := range tests {