Fix dlsym error 'Could not find symbol "file_logger_initialize"'
Fix dlsym error 'Could not find symbol "file_logger_initialize"'

Wrap file_logger_initialize into extern "C" to prevent name mangling,
which caused the error above.

Change-Id: I8c8e1e61599f2afb6dedf4e0b71c0a5a013ccbb7
Reviewed-on: http://review.couchbase.org/86829
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine