bee-cache: Fix bug when --tmpinstall is pointing to local directory

Only care about regular files when tmpinstalling...
Merge branch 'fixes'

* fixes:
  bee-cache: Fix bug when --tmpinstall is pointing to local directory
Revert "beesh: Disable check_rebuild"

This reverts commit 7a80856ea3d14da172d5d43dd240cab75b3cc065.

Reenable check_rebuild to prevent messing up the repository.

Since this happend recently it is better to have this check and complain.
beesh: improve warnings in check_rebuild
beesh: Fix missing redirect of error message