Downgrade grunt-contrib-cssmin.

v0.12.0-v0.12.1 breaks paths in URL.

package.json

@@ -42,7 +42,7 @@
     "grunt-contrib-connect": "~0.9.0",
     "grunt-contrib-copy": "~0.7.0",
     "grunt-contrib-csslint": "~0.4.0",
-    "grunt-contrib-cssmin": "~0.12.1",
+    "grunt-contrib-cssmin": "~0.11.0",
     "grunt-contrib-jade": "~0.14.1",
     "grunt-contrib-jshint": "~0.11.0",
     "grunt-contrib-less": "~1.0.0",

test-infra/npm-shrinkwrap.json

@@ -1184,8 +1184,8 @@
       }
     },
     "grunt-contrib-cssmin": {
-      "version": "0.12.1",
-      "resolved": "https://registry.npmjs.org/grunt-contrib-cssmin/-/grunt-contrib-cssmin-0.12.1.tgz",
+      "version": "0.11.0",
+      "resolved": "https://registry.npmjs.org/grunt-contrib-cssmin/-/grunt-contrib-cssmin-0.11.0.tgz",
       "dependencies": {
         "chalk": {
           "version": "0.5.1",