ensure we have the last file of a minute in realtime mode

gridded_glm/libexec/_minute_gridder.py

@@ -330,6 +330,9 @@ if __name__ == '__main__':
         if len(fileglob) != 3:
             log.error("There are not (yet) three GLM files from this minute. This may be expected. Exiting.")
             exit(0)
+        if sorted(fileglob)[-1] != args.filenames[0]:
+            log.error("This is not the last file from this minute. Exiting.")
+            exit(0)
         args.filenames = fileglob
 
     # check that all of our inputs exist