Fix --mobile=false CLI flag and use it for DBW (#721)

lighthouse-cli/index.js

@@ -87,6 +87,7 @@ Example: --output-path=./lighthouse-results.html`
     'save-artifacts',
     'list-all-audits',
     'list-trace-categories',
+    'mobile',
     'perf',
     'skip-autolaunch',
     'select-chrome',

package.json

@@ -22,7 +22,7 @@
     "closure": "cd lighthouse-core && closure/closure-type-checking.js",
     "watch": "lighthouse-core/scripts/run-mocha.sh --watch",
     "chrome": "lighthouse-core/scripts/launch-chrome.sh",
-    "dbw": "npm run start -- --config-path=lighthouse-core/config/dobetterweb.json --output=html --output-path=results.html"
+    "dbw": "npm run start -- --config-path=lighthouse-core/config/dobetterweb.json --mobile=false --output=html --output-path=results.html"
   },
   "devDependencies": {
     "coveralls": "^2.11.9",