THRIFT: generic output handler

THRIFT: generic output handler

Summary: I'm tired of getting output from thrift via perror AND exceptions, so
this class allows the client to set an alternate (or empty) handler for error
output

Reviewed By: mcslee

Test Plan: I ran on the worker with the default, got output via perror, then
overloaded with my own function and got output via syslog and then NULL

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665131 13f79535-47bb-0310-9956-ffa450edef68