npm-keyword

I've found that npm-keyword doesn't work if your .npmrc has a private npm registry configured that requires authentication. It always gets 401 responses. I've tested the following with a .npmrc with a private registry and without. Without a private registry and _auth, the getAuth function returns undefined and it behaves as it always has. All 11 tests pass. With a .npmrc, I ran npm test and all but the two count tests succeeded. I think this is more a problem with our private registry's API. Without the change, nothing passes. Example of .npmrc I hope you consider this pull request. Thanks!