Fix reading password from stdin
Fix reading password from stdin

This fixes a bug introduced in #585, it must by checked for stdin and
stdout separately whether it is a terminal.

restic/restic,ar-jan/restic,jayme-github/restic,middelink/restic,middelink/restic,byo/restic,ckemper67/restic,kurin/restic,fawick/restic,byo/restic,stuertz/restic,jayme-github/restic,restic/restic,kurin/restic,fawick/restic,ar-jan/restic,stuertz/restic,arithmetric/restic