gstlal_inspiral: relax some command line checks

- I recently tried to increase the strictness of the command line checking to get more informative error messages out of the code and it looks like I made some checks too strict.  this relaxes them a bit

gstlal-inspiral/bin/gstlal_inspiral

@@ -567,7 +567,7 @@ offsetvectors = lsctables.TimeSlideTable.get_table(ligolw_utils.load_filename(op
 all_instruments = reduce(lambda a, b: a | set(b), offsetvectors, set())
 if len(all_instruments) < options.min_instruments:
 	raise ValueError("--time-slide-file \"%s\" names %s but we need at least %d instruments" % (options.time_slide_file, ", ".join(sorted(all_instruments)), options.min_instruments))
-if all_instruments != set(detectors.channel_dict):
+if not (all_instruments >= set(detectors.channel_dict)):
 	raise ValueError("--time-slide-file names %s but have channel names for %s" % (", ".join(sorted(all_instruments)), ", ".join(sorted(detectors.channel_dict))))
 
 
@@ -583,8 +583,8 @@ if all_instruments != set(detectors.channel_dict):
 
 if options.reference_psd is not None:
 	psd = lal.series.read_psd_xmldoc(ligolw_utils.load_filename(options.reference_psd, verbose = options.verbose, contenthandler = lal.series.PSDContentHandler))
-	if set(psd) < all_instruments:
-		raise ValueError("missing PSD(s) for %s" % ", ".join(sorted(all_instruments - set(psd))))
+	if set(psd) != set(detectors.channel_dict):
+		raise ValueError("missing PSD(s) for %s" % ", ".join(sorted(set(detectors.channel_dict) - set(psd))))
 else:
 	psd = dict.fromkeys(all_instruments, None)