Previously we required network-online.target for multi-user.target. This
has made a lot of people very angry and has been widely regarded as a
bad move (or at least, very nonstandard):
15d761a525 (commitcomment-128564097)
This was done because of fragile tests and services declaring
dependencies on multi-user.target when they meant network-online.target.
Let's rip off the bandaid and fix our tests.