sometimes /proc/1/cgroup is not readable

Prevent the code from throwing fatal exceptions when /proc/1/cgroup
exists but is not readable (which can happen in VPS systems).
Merge pull request #11629 from herzi/develop

sometimes /proc/1/cgroup is not readable
Fix suggestions logic

This code was previously repeating the same action (setting the
suggestions key for the given package to list(provides) once for every
element in the set. While this did not produce a functionally incorrect
result, it is unnecessary and poorly-constructed as-is. This commit
simplifies the logic, and only performs that action once.
Remove unused variables
Fix typo
Merge pull request #11651 from johtso/patch-1

Fix typo
Merge pull request #11648 from terminalmage/yum-cleanup

Fix suggestions logic
Revert "Fix broken pillar and broken grains context inside rendered pillars."

This reverts commit 8ac3aad48aa26fcb445dbcecdf8c639be92d8558.
Merge pull request #11654 from s0undt3ch/develop

Revert "Fix broken pillar and broken grains context inside rendered pillars"
Allow standalone execution
Allow standalone test execution
Allow standalone test execution
Allow standalone test execution
Allow standalone test execution
Allow standalone test execution
Allow standalone test execution
Allow standalone test execution
Allow standalone test execution
Allow standalone test execution
Allow standalone test execution