Remove inner exception for UnableToConnectToHost. Fixes #1035

This improves diagnostics by removing potentially-confusing or distracting information.

Author: bgrainger

src/MySqlConnector/Core/ServerSession.cs

@@ -1008,11 +1008,11 @@ private async Task<bool> OpenTcpSocketAsync(ConnectionSettings cs, ILoadBalancer
 #endif
 								}
 							}
-							catch (ObjectDisposedException ex) when (cancellationToken.IsCancellationRequested)
+							catch (ObjectDisposedException) when (cancellationToken.IsCancellationRequested)
 							{
 								SafeDispose(ref tcpClient);
 								Log.Info("Session{0} connect timeout expired connecting to IpAddress {1} for HostName '{2}'", m_logArguments[0], ipAddress, hostName);
-								throw new MySqlException(MySqlErrorCode.UnableToConnectToHost, "Connect Timeout expired.", ex);
+								throw new MySqlException(MySqlErrorCode.UnableToConnectToHost, "Connect Timeout expired.");
 							}
 						}
 					}
@@ -1069,10 +1069,10 @@ private async Task<bool> OpenUnixSocketAsync(ConnectionSettings cs, IOBehavior i
 							socket.Connect(unixEp);
 						}
 					}
-					catch (ObjectDisposedException ex) when (cancellationToken.IsCancellationRequested)
+					catch (ObjectDisposedException) when (cancellationToken.IsCancellationRequested)
 					{
 						Log.Info("Session{0} connect timeout expired connecting to UNIX Socket '{1}'", m_logArguments);
-						throw new MySqlException(MySqlErrorCode.UnableToConnectToHost, "Connect Timeout expired.", ex);
+						throw new MySqlException(MySqlErrorCode.UnableToConnectToHost, "Connect Timeout expired.");
 					}
 				}
 			}
@@ -1126,7 +1126,7 @@ private async Task<bool> OpenNamedPipeAsync(ConnectionSettings cs, int startTick
 					{
 						m_logArguments[1] = cs.PipeName;
 						Log.Info("Session{0} connect timeout expired connecting to named pipe '{1}'", m_logArguments);
-						throw new MySqlException(MySqlErrorCode.UnableToConnectToHost, "Connect Timeout expired.", ex);
+						throw new MySqlException(MySqlErrorCode.UnableToConnectToHost, "Connect Timeout expired.");
 					}
 				}
 			}

src/MySqlConnector/MySqlConnection.cs

@@ -422,10 +422,10 @@ internal async Task OpenAsync(IOBehavior? ioBehavior, CancellationToken cancella
 				cancellationToken.ThrowIfCancellationRequested();
 				throw;
 			}
-			catch (SocketException ex)
+			catch (SocketException)
 			{
 				SetState(ConnectionState.Closed);
-				throw new MySqlException(MySqlErrorCode.UnableToConnectToHost, "Unable to connect to any of the specified MySQL hosts.", ex);
+				throw new MySqlException(MySqlErrorCode.UnableToConnectToHost, "Unable to connect to any of the specified MySQL hosts.");
 			}
 
 #if !NETSTANDARD1_3
@@ -885,10 +885,10 @@ private async ValueTask<ServerSession> CreateSessionAsync(ConnectionPool? pool,
 					return session;
 				}
 			}
-			catch (OperationCanceledException ex) when (timeoutSource?.IsCancellationRequested ?? false)
+			catch (OperationCanceledException) when (timeoutSource?.IsCancellationRequested ?? false)
 			{
 				var messageSuffix = (pool?.IsEmpty ?? false) ? " All pooled connections are in use." : "";
-				throw new MySqlException(MySqlErrorCode.UnableToConnectToHost, "Connect Timeout expired." + messageSuffix, ex);
+				throw new MySqlException(MySqlErrorCode.UnableToConnectToHost, "Connect Timeout expired." + messageSuffix);
 			}
 			catch (MySqlException ex) when ((timeoutSource?.IsCancellationRequested ?? false) || (ex.ErrorCode == MySqlErrorCode.CommandTimeoutExpired))
 			{