SHA1, Session: Fixed documentation for SHA1 encode function and a problem with session init.

Fixed documentation for SHA1 encode function:
The length parameter is obviously used for data_in not for data_out as data_out is always the same length with sha1.

Session init did not save the correct path using store_name in session_store_path.
All session files were getting stored in /dev/shm/duda_session instead of /dev/shm/duda_session/store_name.