bus: write debug message when we get a method call we cannot handle
bus: make sure sd_bus_emit_properties_changed_strv() doesn't return ENOENT if no properties with a change flag are in the interface
log: als turn on debug logging in non-PID1 if /proc/cmdline contains "debug"
util: when we try to read /proc/cmdline in a container, read /proc/1/cmdline instead