pkg/lib/get-timesync-backend.py: Add '/lib' to root directories list

Extend list of root directories to parse with new entry: '/lib'. On
most systems this is just a symlink to '/usr/bin' and everything works
as expected, but it may not be the case for custom distributions,
i.e. ones created using Yocto.

Extending the list fixes problems with Time Management tab on such
systems.

Signed-off-by: Witold Lipieta <[email protected]>

pkg/lib/get-timesync-backend.py

@@ -4,7 +4,7 @@
 # get-timesync-backend - determine which NTP backend unit timedatectl
 #                        will likely enable.
 
-roots = ["/etc", "/run", "/usr/local", "/usr/lib"]
+roots = ["/etc", "/run", "/usr/local", "/usr/lib", "/lib"]
 
 
 def gather_files(name, suffix):