frame_fetch_gwpy failing for low-latency followup

We modified the frame_fetch_gwpy function to be more clever about pulling data from the lldetchar frames. Unfortunately, it still needs some tuning:

https://ldas-jobs.ligo-wa.caltech.edu/~lockloss/events/all/1221600668/condor_analyze/out

2018-09-21 14:31:11,027 executing followup: refine_event(1221600668)
Missing segments: 
[1221600608 ... 1221600683)
Traceback (most recent call last):
  File "/home/lockloss/src/locklost/locklost/analyze.py", line 29, in analyze_event
    func(event)
  File "/home/lockloss/src/locklost/locklost/plugins/refine.py", line 97, in refine_event
    bufs = data.fetch(channels, segment)
  File "/home/lockloss/src/locklost/locklost/data.py", line 167, in fetch
    return func(channels, start, stop)
  File "/home/lockloss/src/locklost/locklost/data.py", line 150, in frame_fetch_gwpy
    frametype=config.IFO+'_R')
  File "/usr/lib/python2.7/site-packages/gwpy/timeseries/core.py", line 1214, in find
    % (observatory, frametype, start, end))
RuntimeError: No H-H1_R frame files found for [1221600608, 1221600683)