mno-async_writes/client: Added unit test to test the connection, request and...

mno-async_writes/client: Added unit test to test the connection, request and linger timeout functionality of xtreemfs::rpc::Client.

git-svn-id: https://xtreemfs.googlecode.com/svn/branches/mno-async_writes@2974 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534