sys: move ForceRemoveAll to integration/client

ForceRemoveAll was only used in tests/fuzzing, but added hcsshim as dependency
for the sys package. Moving this to integration/client makes the "sys" package
slightly more lightweight, and may help simplifying dependency-management.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

sys/filesys_unix.go

@@ -21,11 +21,6 @@ package sys
 
 import "os"
 
-// ForceRemoveAll on unix is just a wrapper for os.RemoveAll
-func ForceRemoveAll(path string) error {
-	return os.RemoveAll(path)
-}
-
 // MkdirAllWithACL is a wrapper for os.MkdirAll on Unix systems.
 func MkdirAllWithACL(path string, perm os.FileMode) error {
 	return os.MkdirAll(path, perm)