Factor out a the start function out of ddfs_get and ddfs_put into ddfs_util.
Work around the dialyzer warning for the LOG_PROTOCOL macro.

Dialyzer warns us that the LOG_PROTOCOL is always false and cannot
match the value of true.  In order to override such a warning, we
use ifdef macro.
Fix the test_chunked_http to support remote master.

The initial test only works when we have a one node cluster.  The new test works
on larger clusters.
Merge pull request #396 from pooya/shayan/ddfs_refactor

Shayan/ddfs refactor