followup: don't fail discovery if lal package not found

locklost/plugins/discover.py

@@ -38,7 +38,11 @@ def discover_data(event):
 
     ### first check if low-latency frames are available
     logging.info("checking if data is available in /dev/shm...")
-    shm_segs = find_shm_segments()
+    try:
+        shm_segs = find_shm_segments()
+    except ImportError as e:
+        logging.info("unable to check /dev/shm: {}".format(e))
+        shm_segs = Segment()
     if query_segs & shm_segs == query_segs:
         shm_end_time = shm_segs[-1][1]
         query_end_time = query_segment[1]