FIX: merging was broken for corrupt packet groups

corrupt session groups can have packet files with multiple APIDs
we handel this by filtering these out and skipping to the next stamp

edosl0util/merge.py

@@ -64,6 +64,11 @@ def read_packet_index(stream):
             LOG.info('dropped %d leading packets', count)
 
         while True:
+            if not packet.stamp:
+                # corrupt packet groups can cause apid mismatch
+                # so skip until we get to the next group
+                packet = stream.next()
+                continue
             ptr = _Ptr(
                 stream.file,
                 stamp=packet.stamp,
@@ -75,6 +80,10 @@ def read_packet_index(stream):
             # collect all packets for this stamp/group
             packet = stream.next()
             while not packet.stamp:
+                # Bail if we're collecting group packets and apids don't match
+                # This means group is corrupt
+                if ptr.apid != packet.apid:
+                    break
                 ptr.size += packet.size
                 ptr.count += 1
                 packet = stream.next()