Fix call for k3s-selinux versions in airgapped environments

[galal-hussein]

Proposed Changes

Fix install script call to get k3s-selinux versions from api.github.com in airgapped environmnets

Types of Changes

Bugfix

Verification

This fix can be verified by installing k3s with selinux enabled in airgapped environment

Linked Issues

• Latest install.sh exits without error message on airgapped nodes #7247

[brandond]

• Bonus points if you replace sourcex with . to fix Fix OpenRC init script errors with sourcex #6739
  

  k3s/install.sh

  Lines 894 to 895 in 4fdaa39

  	if [ -f /etc/environment ]; then sourcex /etc/environment; fi
  	if [ -f ${FILE_K3S_ENV} ]; then sourcex ${FILE_K3S_ENV}; fi