gstlal_inspiral_plot_sensitivity: iterate over all time_slide_ids

The original expression only considered the first time_slide_id in the
database.

gstlal-inspiral/bin/gstlal_inspiral_plot_sensitivity

@@ -126,7 +126,7 @@ class upper_limit(object):
         '''
         # get instruments with sngl-sngl coincidences in zero lag
         sngl_sngl_id, = connection.cursor().execute("SELECT coinc_def_id FROM coinc_definer WHERE search == 'inspiral' AND description == 'sngl_inspiral<-->sngl_inspiral coincidences';").fetchone()
-        time_slide_ids = connection.cursor().execute("SELECT distinct(time_slide_id) FROM time_slide;").fetchone()
+        time_slide_ids = [row[0] for row in connection.cursor().execute("SELECT distinct(time_slide_id) FROM time_slide;")]
 
         zero_lag_ids = []
         for tsid in time_slide_ids: