fail to create diagnostic file when -b is used

turris-diagnostics fails to create file when -b is used.

Foris-controller uses -b to suppress output, which won't be read anyway.

How to reproduce

  • turris-diagnostics: 13.1
  • TOS: HBL-5.2.0
/usr/share/diagnostics/diagnostics.sh -b -o /tmp/diagnostics-deadbeef.out firewall

Expected result

root@turris:~# ls /tmp/diagnostics*
diagnostics-deadbeef.out

Actual result

root@turris:~# ls /tmp/diagnostics-*
ls: /tmp/diagnostics-*: No such file or directory

What works

/usr/share/diagnostics/diagnostics.sh -o /tmp/diagnostics-deadbeef.out firewall