fix out of range access

this is broken since 6e4a21ff22345a24e4d530725814c436a1bdd49a
the original commit in 2001.

I imagine the idea was to strip a trailing sal_Unicode(11) from the
end of the string and then recalculate if the string is empty, but
seeing as it has chugged away for the last 12+ years like this I'm
relunctant to change it to what it might have originally been
intended to do and instead just remove the stuff which was never
executed.

Change-Id: I73d5108ece8e716d78a4898117e0ee2d51822015