discovery: don't use /dev/shm data source

The low-latency /dev/shm frames don't have all the data, and we're not
checking that the plugins are only using data available in the low-latency
frames, so don't ok analysis based on the presence of those frames, and
instead wait for the full frames on disk.  This should help prevent some
data missing errors.

locklost/plugins/discover.py

@@ -35,27 +35,27 @@ def discover_data(event):
     query_segs = SegmentList([query_segment])
     logging.info("querying for data in range: {} - {}".format(*query_segment))
 
-    ### first check if low-latency frames are available
-    logging.info("checking if data is available in /dev/shm...")
-    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]
+    # ### first check if low-latency frames are available
+    # logging.info("checking if data is available in /dev/shm...")
+    # 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]
 
-        ### check if time requested is too new, if so,
-        ### sleep until it is available
-        if query_end_time > shm_end_time:
-            time.sleep(query_end_time - shm_end_time)
-            shm_segs = find_shm_segments()
+    #     ### check if time requested is too new, if so,
+    #     ### sleep until it is available
+    #     if query_end_time > shm_end_time:
+    #         time.sleep(query_end_time - shm_end_time)
+    #         shm_segs = find_shm_segments()
 
-        ### check if span of data requested is all available
-        if query_segs & shm_segs == query_segs:
-            logging.info("queried data available in /dev/shm")
-            return True
+    #     ### check if span of data requested is all available
+    #     if query_segs & shm_segs == query_segs:
+    #         logging.info("queried data available in /dev/shm")
+    #         return True
 
     ### if shm frames are not available for the time requested,
     ### wait until raw frames from LDR are available