Fix exception on clock skew (#202)

* Fix exception on clock skew

* Return device name instead of db object

lib/pairing.js

@@ -74,14 +74,7 @@ function isPaired (deviceId) {
   const sql = 'select device_id, name from devices where device_id=$1 and paired=TRUE'
 
   return db.oneOrNone(sql, [deviceId])
-    .then(row => {
-      const deviceName = row.name
-      const isDevicePaired = row && row.device_id === deviceId
-      return {
-        deviceName: deviceName,
-        isDevicePaired: isDevicePaired
-      }
-    })
+    .then(row => row && row.device_id === deviceId ? row.name : false)
 }
 
 module.exports = {pair, unpair, authorizeCaDownload, isPaired}