Fix spelling error in docs
Fix spelling error in docs

Resulting in lintian complain:
I: vdirsyncer: spelling-error-in-manpage usr/share/man/man1/vdirsyncer.1.gz errorneous erroneous

hobarrera/vdirsyncer,untitaker/vdirsyncer,hobarrera/vdirsyncer,untitaker/vdirsyncer,untitaker/vdirsyncer