Make code more complain with node 6

Author: armano2

Diff for: lib/rules/use-v-on-exact.js

@@ -43,11 +43,8 @@ module.exports = {
               return rv
             }, {})
 
-          const directives = Object.keys(groups).map(key => groups[key])
-          // const directives = Object.values(groups) // Uncomment after node 6 is dropped
-            .filter(item => item.length > 1)
-          for (const group of directives) {
-            if (group.some(item => item.modifiers.length > 0)) { // check if there are directives with modifiers
+          for (const group of groups) {
+            if (group.length > 1 && group.some(item => item.modifiers.length > 0)) { // check if there are directives with modifiers
               const invalid = group.filter(item => item.modifiers.length === 0)
               for (const node of invalid) {
                 context.report({