Keep outer folder for renamed archives with containing a single folder

With this change the contents of a decrypted and extracted archive can
always be found in a folder named like the archive. This avoids confusion
for archives containing a single folder with a completely different name.

Improves: 44a0d67d172d3c68ff408bcffa0af89900189bce
(cherry picked from commit d78aed361f39db75da8d36cdde5c656599aea34e)

• GnuPG-bug-id: T8154