Automatic merge from submit-queue (batch tested with PRs 60476, 62462, 61391, 62535, 62394). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Revert "git: Use VolumeHost.GetExec() to execute stuff in volume plugins"
This reverts commit c578542ad7 (PR #51098). The PR added support for containerized git, on the other hand it required git 1.8.5. This breaks git volumes on older distros (CentOS 7, Ubuntu 14.04) that have old git.
Git volumes are getting deprecated (https://github.com/kubernetes/kubernetes/issues/60999) so we should restore it to the last working state and not touch it any longer.
**Release note**:
```release-note
gitRepo volumes in pods no longer require git 1.8.5 or newer, older git versions are supported too now.
```
I'd like to cherry-pick it into 1.10.
/sig storage
3e4268f580