Removing volume directory fix

Directory mounted in the container wasn't removed along the container
so we ended up with a lot of empty directories on the server.

containers/tools.go

@@ -62,7 +62,7 @@ func du(path string) (int, int, error) {
 	return space, inodes, nil
 }
 
-// Removes content of given directory
+// Removes content of given directory and then the directory itself
 func removeDirectory(dir string) error {
 	d, err := os.Open(dir)
 	if err != nil {
@@ -79,6 +79,12 @@ func removeDirectory(dir string) error {
 			return err
 		}
 	}
+
+	err = os.Remove(filepath.Join(dir))
+	if err != nil {
+		return err
+	}
+
 	return nil
 }