libdokan: helper function for obfuscating file name
libdokan: helper function for obfuscating file name

Suggested by jakob223.

Issue: #17979

keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client