Backout Squirrel modules to support update / insert of Windows shortcuts

related to issue #1181

Auditors: @bbondy

Test Plan:

  Installation on Windows should operate as in previous versions.
  Both updates and installs will update existing shortcuts
  and re-create shortcuts if they do not exist.

package.json

@@ -80,7 +80,7 @@
     "async": "^2.0.1",
     "electron-localshortcut": "^0.6.0",
     "electron-prebuilt": "brave/electron-prebuilt",
-    "electron-squirrel-startup": "brave/electron-squirrel-startup",
+    "electron-squirrel-startup": "^1.0.0",
     "file-loader": "^0.8.5",
     "font-awesome": "^4.5.0",
     "font-awesome-webpack": "0.0.4",
@@ -127,7 +127,7 @@
     "electron-builder": "^2.3.1",
     "electron-packager": "brave/electron-packager",
     "electron-rebuild": "^1.1.1",
-    "electron-winstaller": "brave/windows-installer",
+    "electron-winstaller": "^2.3.0",
     "empty-port": "0.0.2",
     "flow-bin": "^0.22.1",
     "gulp": "^3.9.0",