Remove non-standard package.json property

This was added in 88ee475
and is not used anymore since a2687fd.

package.json

@@ -1,6 +1,5 @@
 {
   "name": "handlebars",
-  "barename": "handlebars",
   "version": "5.0.0-alpha.1",
   "description": "Handlebars provides the power necessary to let you build semantic templates effectively with no frustration",
   "homepage": "http://www.handlebarsjs.com/",