libnetwork/internal/kvstore/boltdb: BoltDB.Get(): don't shadow error

Don't shadow the original error if we got one.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

libnetwork/internal/kvstore/boltdb/boltdb.go

@@ -139,13 +139,12 @@ func (b *BoltDB) Get(key string) (*store.KVPair, error) {
 
 		return nil
 	})
-
-	if len(val) == 0 {
-		return nil, store.ErrKeyNotFound
-	}
 	if err != nil {
 		return nil, err
 	}
+	if len(val) == 0 {
+		return nil, store.ErrKeyNotFound
+	}
 
 	dbIndex := binary.LittleEndian.Uint64(val[:libkvmetadatalen])
 	val = val[libkvmetadatalen:]