Initialise variable in stringForKey
Initialise variable in stringForKey

Init the ``string`` variable in stringForKey to prevent compiler errors with ``-Wsometimes-uninitialised``.
TimBroddin/SimpleKeychain,auth0/SimpleKeychain,bensonday/SimpleKeychain,auth0/SimpleKeychain,bensonday/SimpleKeychain,TimBroddin/SimpleKeychain,bensonday/SimpleKeychain,TimBroddin/SimpleKeychain