-- fix read timeout handling in TSocket

-- fix read timeout handling in TSocket

Summary:
- turns out that EAGAIN can be returned both when there is a transmission timeout and when there
  is a lack of system resources.

This diff has a hacky fix for respecting a user specified read timeout.

Reviewed By: Steve Grimm, Marc, Slee

Test Plan:
- Tested by trying to crash an srp machine

Revert Plan: No.

Notes:
- Also added functionality to allow users to specify the max number of recv retries (in the case
  when EAGAIN is returned due to a lack of system resources)

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665121 13f79535-47bb-0310-9956-ffa450edef68