Improve initialization speed - avoid traversing sysfs about fclones HOT 4 CLOSED

 > /usr/lib/x86_64-linux-gnu/libc-2.33.so(close+0x3b) [0x10832b]
 > /usr/lib/x86_64-linux-gnu/libudev.so.1.7.0(udev_monitor_receive_device+0x17d8) [0x138a8]
 > /usr/lib/x86_64-linux-gnu/libudev.so.1.7.0(udev_monitor_receive_device+0x9de2) [0x1beb2]
 > /usr/lib/x86_64-linux-gnu/libudev.so.1.7.0() [0x71e7]
 > /usr/lib/x86_64-linux-gnu/libudev.so.1.7.0() [0x770b]
 > /usr/lib/x86_64-linux-gnu/libudev.so.1.7.0(udev_device_get_properties_list_entry+0x6de) [0xfb6e]
 > /usr/lib/x86_64-linux-gnu/libudev.so.1.7.0(udev_device_get_properties_list_entry+0xb73) [0x10003]
 > /usr/lib/x86_64-linux-gnu/libudev.so.1.7.0(udev_enumerate_scan_devices+0x289) [0x114b9]
 > /home/xxx/.cargo/bin/fclones(block_utils::get_parent_devpath_from_path+0x47) [0xf14d7]
 > /home/xxx/.cargo/bin/fclones(fclones::device::DiskDevices::new+0x1dd) [0xf068d]
 > /home/xxx/.cargo/bin/fclones(fclones::group_files+0x65) [0xffbf5]
 > /home/xxx/.cargo/bin/fclones(fclones::main+0x927) [0x1769d7]
 > /home/xxx/.cargo/bin/fclones(std::sys_common::backtrace::__rust_begin_short_backtrace+0x3) [0x17b2e3]
 > /home/xxx/.cargo/bin/fclones(_ZN3std2rt10lang_start28_$u7b$$u7b$closure$u7d$$u7d$17hf452a67b20fd31b4E.llvm.9150410927396584600+0x9) [0x1770b9]
 > /home/xxx/.cargo/bin/fclones(std::rt::lang_start_internal+0x305) [0x248425]
 > /home/xxx/.cargo/bin/fclones(main+0x22) [0x176c52]
 > /usr/lib/x86_64-linux-gnu/libc-2.33.so(__libc_start_main+0xd5) [0x28565]
 > /home/xxx/.cargo/bin/fclones(_start+0x2e) [0x4b0ee]