Clean: remove small files

Clean: remove small files

*policy.hpp
 No affect to Window Manager decision, so remove it.
*config.hpp, config.cpp
 Small function to hold the path information to config file,
 but no need to hold until the death of process.
 So move it to stack variable, then remove files.

Change-Id: I6c210acc586c7cc048e0b158df5e3a511f927b9d
Signed-off-by: Kazumasa Mitsunari <knimitz@witz-inc.co.jp>