mountlib: fix race condition in cache clear
mountlib: fix race condition in cache clear

ncw/rclone,yonjah/rclone,B4dM4n/rclone,B4dM4n/rclone,yonjah/rclone,seuffert/rclone,yonjah/rclone,seuffert/rclone,olihey/rclone,olihey/rclone,B4dM4n/rclone,olihey/rclone,seuffert/rclone,ncw/rclone,yonjah/rclone,ncw/rclone,ncw/rclone,seuffert/rclone,B4dM4n/rclone,olihey/rclone