Fixed use of bare vars on agent2 tasks for linux

[danilomendes]

• Added bool filter on zabbix_agent2 and zabbix_agent_package_remove vars
• Removed implicit conditionals on psk files vars when "is defined" should be enough

SUMMARY

Those tasks began to fail in my setup, and I found this note on ansible docs: "In 2.10 the default setting for conditional_bare_variables will change to false. In 2.12 the old behavior will be deprecated." (https://docs.ansible.com/ansible/latest/porting_guides/porting_guide_2.8.html). The hints I found on my logs are the same on #662 and #655.

These commits resolved the issue for me.

Fixes #662
Fixes #655

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

zabbix_agent

ADDITIONAL INFORMATION

when:
  - zabbix_agent2_tlspskfile is defined
  - zabbix_agent2_tlspskfile

I could not get exactly what was the intention of the second check. Since it is after the first "is defined" check, I assumed it was to check implicitly if it is an valid string (maybe not empty). I removed it (this second line) because I think the first check makes it safe enough and I can think a better way to ensure it is a valid filename.

[dj-wasabi]

Thanks! 👍

[shk3bq4d]

I could not get exactly what was the intention of the second check. Since it is after the first "is defined" check, I assumed it was to check implicitly if it is an valid string (maybe not empty). I removed it (this second line) because I think the first check makes it safe enough and I can think a better way to ensure it is a valid filename.

reasoning is explained in #515

I have opened #680 to revert your change on this specific point

[D3DeFi]

@dj-wasabi can you check the regression issue please? I would like to release 1.7.0 in the following days and feel like this should be addressed before than