Make sure what loadPkg returns has a "keywords"

loadPkg should always return a complete config which has a "keywords" field. For empty cases, return the empty array as "keywords" field of the config.
Remove useless else logic from loadPkg

Removing that return is the better fix for this. The keywords list
is already set to an empty array and won’t change outside that `if`
clause.
Merge pull request #1 from mostafah/patch-1

Make sure what loadPkg returns has a "keywords"
Merge pull request #4 from jonschlinkert/master

merge pr from @mostafah