Fix .ssh directory rights

[NoWiS-]

Problem

• ssh connection fails due to bad permissions:

  Jul  9 17:31:58 XXX sshd[240651]: Authentication refused: bad ownership or modes for file /home/BORG_USER/.ssh/authorized_keys
  Jul  9 17:31:58 XXX sshd[240651]: Failed publickey for BORG_USER from IP port PORT ssh2: PUBLIC_KEY_SIGNATURE

Solution

• Update rights.

PR Status

• [x] Code finished and ready to be reviewed/tested
• [ ] The fix/enhancement were manually tested (if applicable)

Automatic tests

Automatic tests can be triggered on https://ci-apps-dev.yunohost.org/ after creating the PR, by commenting "!testme", "!gogogadgetoci" or "By the power of systemd, I invoke The Great App CI to test this Pull Request!". (N.B. : for this to work you need to be a member of the Yunohost-Apps organization)

[NoWiS-]

!gogogadgetoci

[zamentur]

!testme

[Salamandar]

Should be incorporated in the current testing branch now.