Return non-zero exit code if none of requested modules exist
If you call diagnostics script with modules that do not exist, it will print warning, no diagnostics output is created, but exit code is 0.
root@turris:~# /usr/share/diagnostics/diagnostics.sh foo bar non-existing-module
!!!!!!!!!!!!!! foo not found
!!!!!!!!!!!!!! bar not found
!!!!!!!!!!!!!! non-existing-module not found
root@turris:~# echo $?
0
Which is fine if you call it from cli by hand, but if you interact with that script from another process (Foris), then exit code 0 is misleading.