Ensure we get a proper retention policy for backups

src/settings.js

@@ -386,7 +386,12 @@ function getBackupConfig(callback) {
         if (error && error.reason === BoxError.NOT_FOUND) return callback(null, gDefaults[exports.BACKUP_CONFIG_KEY]);
         if (error) return callback(error);
 
-        callback(null, JSON.parse(value)); // provider, token, password, region, prefix, bucket
+        var tmp = JSON.parse(value);
+
+        // ensure we have a proper retention policy, the rest api checks for validity on settings at the moment
+        if (!tmp.retentionPolicy || Object.keys(tmp.retentionPolicy) === 0) tmp.retentionPolicy = gDefaults[exports.BACKUP_CONFIG_KEY].retentionPolicy;
+
+        callback(null, tmp); // provider, token, password, region, prefix, bucket
     });
 }