Fix variable unpacking mismatch in bootanalyze.py

Fix variable unpacking mismatch in bootanalyze.py

Fix for the below mismatch that I've seen in recent boot time runs

BootAnimEnd time or BootComplete-kernel not captured in both log,
cannot get time diff
    main()
  File "system/extras/boottime_tools/bootanalyze/bootanalyze.py", line 123, in main
    error_time, components_to_monitor)
ValueError: need more than 4 values to unpack

Test: no unpack mismatch in recent runs
Change-Id: I4d39453964b9b4036d6c0aaff6cac1b030865445