Fix bug when parsing OAuth2 response.

Author: qimingyuan

Dropbox.Api/DropboxOauth2Helper.cs

@@ -321,8 +321,6 @@ public static OAuth2Response ParseTokenFragment(Uri redirectedUri)
                     case "token_type":
                         tokenType = Uri.UnescapeDataString(elements[1]);
                         break;
-                    default:
-                        throw new ArgumentException("Unexpected values in fragment", "redirectedUri");
                 }
             }
 
@@ -460,8 +458,6 @@ public static Task<OAuth2Response> ProcessCodeFlowAsync(Uri responseUri, string
                         }
 
                         break;
-                    default:
-                        throw new ArgumentException("The responseUri contains unexpected values in the query component.", "responseUri");
                 }
             }