Bug 15447 - log4perl.conf does not have __LOG_DIR__ replaced when installing

Bug 15447 - log4perl.conf does not have __LOG_DIR__ replaced when installing

Since the introduction of Koha::Logger, it appears that the
log4perl.conf config file has been broken. The references to __LOG_DIR__
is not being replaced.

Test Plan:
1) Apply this patch
2) Run 'perl Makefile.PL'
3) Run 'make'
4) Open blib/KOHA_CONF_DIR/log4perl.conf with a text editor
5) Note the log file paths are correctly set, and do not have
   __LOG_DIR__ in them.

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>