fix: error on distros without VERSION_ID on /etc/os-release

[yulken]

Proposed Changes

Types of Changes

Verification

Testing

Linked Issues

• Installing K3s on OS without VERSION_ID #8723

User-Facing Change

Further Comments

[brandond]

What distro has an os-release file with no VERSION_ID?

[yulken]

@brandond I've linked an issue where this behavior was detected.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 19.91%. Comparing base (b33b713) to head (4069af0).
Report is 2 commits behind head on master.

❗ There is a different number of reports uploaded between BASE (b33b713) and HEAD (4069af0). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (b33b713)	HEAD (4069af0)
e2etests	1	0

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #12440       +/-   ##
===========================================
- Coverage   40.56%   19.91%   -20.65%     
===========================================
  Files         187      184        -3     
  Lines       19286    19221       -65     
===========================================
- Hits         7823     3828     -3995     
- Misses      10275    14962     +4687     
+ Partials     1188      431      -757     

Flag	Coverage Δ
e2etests	?
unittests	19.91% <ø> (ø)

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[brandond]

No backports necessary for install script changes.