smurf: Update list of CSO fits.

Updated list of CSO fits for the period 20140404 through 20140531. Also
updated 20120912, a night with bad spikes to be slightly better.
smurf: Update is_wvm_useable.

Added 20120912 to the list of nights to use the CSO fits by default. Browsing
the fault 20120724.004 - WVM showing noise spikes showed that night as
having bad spikes, but it was never added to the exceptions list.