CA-389345: fix incorrect data type in python3

[chunjiez]

even if turning igmp snooping on in ovs bridge, if there is no
external querier multicast traffic, ovs igmp snooping will not
work, so we need to inject igmp traffic

[minglumlu]

Good catch!
No one checks this part in the script (neither unit test, nor the xenopsd for the result), so it failed quietly. And the final result relies on the igmp router to send the query periodically.

[psafont]

I've never seen this error before (happening in CI):

   ⬇ retrieved dune.3.15.3  (https://opam.ocaml.org/cache)
  [ERROR] The compilation of dune.3.15.3 failed at "ocaml boot/bootstrap.ml -j 3".
  
  #=== ERROR while compiling dune.3.15.3 ========================================#
  # context     2.2.0 | linux/x86_64 | ocaml-base-compiler.4.14.2 | git+https://github.com/xapi-project/xs-opam.git
  # path        ~/work/xen-api/xen-api/_opam/.opam-switch/build/dune.3.15.3
  # command     ~/.opam/opam-init/hooks/sandbox.sh build ocaml boot/bootstrap.ml -j 3
  # exit-code   1
  # env-file    ~/.opam/log/dune-3086-d777a4.env
  # output-file ~/.opam/log/dune-3086-d777a4.out
  ### output ###
  # /home/runner/work/xen-api/xen-api/_opam/bin/ocamlrun: /lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.35' not found (required by /home/runner/work/xen-api/xen-api/_opam/bin/ocamlrun)
  # /home/runner/work/xen-api/xen-api/_opam/bin/ocamlrun: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.33' not found (required by /home/runner/work/xen-api/xen-api/_opam/bin/ocamlrun)
  # /home/runner/work/xen-api/xen-api/_opam/bin/ocamlrun: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.34' not found (required by /home/runner/work/xen-api/xen-api/_opam/bin/ocamlrun)

[psafont]

Seems like it was a caching issue

[gangj]

@chunjiez
May I know more about the fix: does this fix resolve the issue in the bug: sometimes there was no traffic got captured at all, while sometimes, it could capture several packages, but the traffic stop soon.
Would you please share more, thank you!