RollingFileAppender does not correctly append on device restart

[CrazyRangerBob]

When using RollingFileAppender the log file will restart from the second logging line when the device is restarted, rather than correctly appending and rolling.

Solution appears to be to switch lines 116 and 117 in RollingFIleAppender.cpp getFile() to

_maxRowLength = readMaxRowLength();
_file.seek(readOffset(), SeekSet);

Otherwise the FS position pointer is left in an incorrect position by the "readMaxRowLength()" operation.