Make triggerOpportunisticLinksUpdate() directly use RefreshLinks

Make triggerOpportunisticLinksUpdate() directly use RefreshLinks

This makes the jobs *actually* end up in the
'refreshLinksPrioritized' queue rather than 'refreshLinks'.
These jobs can run fast in a higher priority queue since the
output is already cached (much of the point of 'prioritize').
They won't if they get stuck behind regular 'refreshLinks'.

This also avoids the indirection of an intermediate job.
The use of lazyPush() is already enough to prevent the user
from experiencing cross-DC RTT overhead.

Change-Id: I5d0440588db09c299cd70191e5624ffc7ebf04c0