loop-util: drop unused .uevent_seqnum_not_before and .timestamp_not_before fields

src/shared/loop-util.h

@@ -26,8 +26,6 @@ struct LoopDevice {
         dev_t backing_devno; /* The backing file's dev_t */
         ino_t backing_inode; /* The backing file's ino_t */
         uint64_t diskseq; /* Block device sequence number, monothonically incremented by the kernel on create/attach, or 0 if we don't know */
-        uint64_t uevent_seqnum_not_before; /* uevent sequm right before we attached the loopback device, or UINT64_MAX if we don't know */
-        usec_t timestamp_not_before; /* CLOCK_MONOTONIC timestamp taken immediately before attaching the loopback device, or USEC_INFINITY if we don't know */
         uint32_t sector_size;
         uint64_t device_size;
 };