Paths do not always have Targets, which means that the previously added powershell
command will return an empty string, causing pods with subpath mounts to fail.
In golang, evalSymlink() does not work if windows disk driver letter is
not assigned. Replace this function with a powershell command to work
around this issue.
This patch removes pkg/util/mount completely, and replaces it with the
mount package now located at k8s.io/utils/mount. The code found at
k8s.io/utils/mount was moved there from pkg/util/mount, so the code is
identical, just no longer in-tree to k/k.
Files in pkg/util/mount that contain significant code implementation for
subpaths are moved to a new package at pkg/volume/util/subpath. This
move is done in order to preserve git history.
