fix: for containers use root-disk detection cleverly (#11593)

root-disk implemented currently had issues where root
disk partitions getting modified might race and provide
incorrect results, to avoid this lets rely again back on
DeviceID and match it instead.

In-case of containers `/data` is one such extra entity that
needs to be verified for root disk, due to how 'overlay'
filesystem works and the 'overlay' presents a completely
different 'device' id - using `/data` as another entity
for fallback helps because our containers describe 'VOLUME'
parameter that allows containers to automatically have a
virtual `/data` that points to the container root path this
can either be at `/` or `/var/lib/` (on different partition)

pkg/disk/disk.go

@@ -30,21 +30,3 @@ type Info struct {
 	Ffree  uint64
 	FSType string
 }
-
-// SameDisk reports whether di1 and di2 describe the same disk.
-func SameDisk(di1, di2 Info) bool {
-	if di1.Total != di2.Total {
-		// disk total size different
-		return false
-	}
-
-	if di1.Files != di2.Files {
-		// disk total inodes different
-		return false
-	}
-
-	// returns true only if Used, Free are same, then its the same disk.
-	// we are deliberately not using free inodes as that is unreliable
-	// due the fact that Ffree can vary even for temporary files
-	return di1.Used == di2.Used && di1.Free == di2.Free
-}