bump npm-shrinkwrap to ~3.1.4

package.json

@@ -56,7 +56,7 @@
     "grunt-sed": "~0.1.1",
     "load-grunt-tasks": "~0.5.0",
     "markdown": "~0.5.0",
-    "npm-shrinkwrap": "~3.1.3",
+    "npm-shrinkwrap": "~3.1.4",
     "time-grunt": "~0.3.2"
   },
   "engines": {

test-infra/npm-shrinkwrap.json

 {
   "name": "bootstrap",
   "version": "3.1.1",
-  "npm-shrinkwrap-version": "3.1.3",
+  "npm-shrinkwrap-version": "3.1.4",
   "dependencies": {
     "btoa": {
       "version": "1.1.2",
@@ -2976,8 +2976,8 @@
       }
     },
     "npm-shrinkwrap": {
-      "version": "3.1.3",
-      "resolved": "https://registry.npmjs.org/npm-shrinkwrap/-/npm-shrinkwrap-3.1.3.tgz",
+      "version": "3.1.4",
+      "resolved": "https://registry.npmjs.org/npm-shrinkwrap/-/npm-shrinkwrap-3.1.4.tgz",
       "dependencies": {
         "array-find": {
           "version": "0.1.1",