Soledad sync check needs python-u1db package installed (Bug #6520)

Change-Id: I8a6c27434f548f24d9dba1a969699200ab307477
Merge branch '6520_soledad_check_needs_python_u1db' into 'develop'

6520 soledad check needs python u1db

https://leap.se/code/issues/6520

See merge request !2