Fix SDL configuration file path Valgrind errors

Fix Valgrind 'conditional jump or move depends on uninitialized value'
errors what are related to boost::filesystem::directory_iterator by
replacing the boost based implementation with standard C 'opendir()'
and 'readdir()' implementation.

Issue-ID: RIC-226

Signed-off-by: Timo Tietavainen <timo.tietavainen@nokia.com>
Change-Id: I011dabaab6dcf602ff16e21e778dcbd12c1a9819