Don't create files in /etc/iproute2 out of thin air

[Infinoid]

Fixes: #164

[Infinoid]

I was not able to run your unit tests; I get a timeout after 10 minutes. Please let me know if it breaks anything else.

I tested this using one of my own tests; it worked for me.

Before patch:

• no /etc/iproute2 directory
• run test (success)
• /etc/iproute2 exists
• /etc/iproute2/group file exists and is empty

After patch:

• no /etc/iproute2 directory
• run test (success)
• no /etc/iproute2 directory

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 50.64%. Comparing base (1f3a281) to head (7cd1773).

Files	Patch %	Lines
pkg/exec.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #165      +/-   ##
==========================================
+ Coverage   50.48%   50.64%   +0.15%     
==========================================
  Files          67       67              
  Lines        3207     3197      -10     
==========================================
  Hits         1619     1619              
+ Misses       1362     1352      -10     
  Partials      226      226              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.