adds specs for file_store

spec/fixtures/files/auth_stored_credentials.json

@@ -1,10 +1,8 @@
-{
-  "access_token":"my_access_token",
-  "authorization_uri":"https://accounts.google.com/o/oauth2/auth",
-  "client_id":"123456_test_client_id@.apps.googleusercontent.com",
-  "client_secret":"123456_client_secret",
-  "expires_in":3600,
-  "refresh_token":"my_refresh_token",
-  "token_credential_uri":"https://accounts.google.com/o/oauth2/token",
-  "issued_at":1384440275
-}
+{   "access_token":"access_token_123456789",
+    "authorization_uri":"https://accounts.google.com/o/oauth2/auth",
+    "client_id":"123456789p.apps.googleusercontent.com",
+    "client_secret":"very_secret",
+    "expires_in":3600,
+    "refresh_token":"refresh_token_12345679",
+    "token_credential_uri":"https://accounts.google.com/o/oauth2/token",
+    "issued_at":1386053761}