Moving the web interface's log4j configuration to a sub-directory

https://github.com/corey-hammerton/graylog2-rpms/issues/4

Files Modified:
SOURCES/sysconfig-graylog2-web-interface
SPECS/graylog2-web-interface.spec

Installing the source log4j-graylog2-web-interface.xml to
/etc/graylog2/web-interface/log4j.xml in
SPECS/graylog2-web-interface.spec.

Changing the path to the logger.file in
SOURCES/sysconfig-graylog2-web-interface to the new path
/etc/graylog2/web-interface/log4j.xml