client: Fixed bug that redirect error was thrown at the first attempt e.g., at...

client: Fixed bug that redirect error was thrown at the first attempt e.g., at mkfs.xtreemfs. Revised structure of execute_sync_request.cpp to increase the readibility.
- Allow multiple redirects in a row although the number of max attempt would prevent this.
- "using namespace" now.
- Log message when retrying was successful.

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@3597 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534