30201
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10923 delete should raise error when there is no file
https://pharo.fogbugz.com/f/cases/10923
Diff information: http://smalltalkhub.com/mc/Pharo/Pharo30/main/FileSystem-Memory-StephaneDucasse.32.diff http://smalltalkhub.com/mc/Pharo/Pharo30/main/FileSystem-Tests-Core-StephaneDucasse.50.diff http://smalltalkhub.com/mc/Pharo/Pharo30/main/FileSystem-Disk-StephaneDucasse.59.diff
