This update for systemd fixes the following issues:

- Add timestamp to D-Bus events to improve traceability (jsc#SLE-21862, jsc#SLE-18102, jsc#SLE-18103)
- Fix IO scheduler udev rules to address performance issues (jsc#SLE-21032, bsc#1192161)
- shutdown: Reduce log level of unmounts (bsc#1191252)
- pid1: make use of new "prohibit_ipc" logging flag in PID 1 (bsc#1189803)
- core: rework how we connect to the bus (bsc#1190325)
- mount-util: fix fd_is_mount_point() when both the parent and directory are network fs (bsc#1190984)
- virt: detect Amazon EC2 Nitro instance (bsc#1190440)
- Several fixes for umount
- busctl: use usec granularity for the timestamp printed by the busctl monitor command
- fix unitialized fields in MountPoint in dm_list_get()
- shutdown: explicitly set a log target
- mount-util: add mount_option_mangle()
- dissect: automatically mark partitions read-only that have a read-only file system
- build-sys: require proper libmount version
- systemd-shutdown: use log_set_prohibit_ipc(true)
- rationalize interface for opening/closing logging
- pid1: when we can't log to journal, remember our fallback log target
- log: remove LOG_TARGET_SAFE pseudo log target
- log: add brief comment for log_set_open_when_needed() and log_set_always_reopen_console()
- log: add new "prohibit_ipc" flag to logging system
- log: make log_set_upgrade_syslog_to_journal() take effect immediately
- dbus: split up bus_done() into seperate functions
- machine-id-setup: generate machine-id from DMI product ID on Amazon EC2
- virt: if we detect Xen by DMI, trust that over CPUID

This update was imported from the SUSE:SLE-15:Update update project.