Bug with .wrap and promises in 0.3.0

[jeff-kilbride]

Version 0.3.0 introduced a bug when using the .wrap method with promises. I have created some new .wrap tests to reproduce the issue and will be submitting a PR to resolve it.

TypeError: Cannot set property 'parse' of undefined
    at Object.self.get (index.js:183:19)
    at Object.self.wrap (node_modules/cache-manager/lib/caching.js:99:20)
    at node_modules/cache-manager/lib/caching.js:48:18
    at wrapPromise (node_modules/cache-manager/lib/caching.js:47:16)
    at Object.self.wrap (node_modules/cache-manager/lib/caching.js:92:20)
    at Context.<anonymous> (test/lib/redis-store-spec.js:507:8)