[V3dot10] Bug in streams

[Keith Hodges]

If you do

    FileStream  oldFileNamed: 'tmp'.

and the file exists you will get a MultiByteFileStream on the file.

if it doesnt exist you will get a StandardFileStream. This is due to 
code in the method below is missing the call to #concreteStream, or 
should read FileStream readOnlyFileNamed:

regards

Keith

=======

StandardFileStream-#fileDoesNotExistUserHandling:
           
....

newName = '' ifFalse: [^ self concreteStream readOnlyFileNamed: (self 
fullName: newName)].

....