RollingFileAppender ignores the application base directory

[勝田均]

I think RollingFileAppender should call ConvertToFullPath(string path) to
get the full path of a log file, but two methods in RollingFileAppender
call Path.GetFullPath(string path) directory.
And many methods of RollingFileAppenderTest should get the full path of a
log file before pass to a constructor of FileInfo, StreamReader and
FileStream.
// KATTA Hitoshi