replace TimeoutException with RequestTimeoutException or ReadTimeoutException

[wtog]

Both Request timeout and Read timeout throw the same java.util.concurrent.TimeoutException java.util.concurrent.TimeoutException: Request timeout to www.baidu.com after 3000 ms

it`s not convenient to catch the real exception

i suggest to throw AhcRequestTimeoutException And AhcReadTimeoutException instead of logging the timeout message in RequestTimeoutTimerTask.java or ReadTimeoutTimerTask.java