Fix a deprecation warning about regex
Fix a deprecation warning about regex

Fix the following deprecation warning.

* DeprecationWarning: Flags not at the start of
  the expression '^tid:(?m)'

Change-Id: I04aede6aec12cf89addeb1c9d500f0c623bba1a5
Closes-Bug: 1987539
Signed-off-by: Takashi Natsume <2c48eb5bf73c355a2d5583bc776dffa383cdf819@gmail.com>

openstack/cinder,mahak/cinder,mahak/cinder,openstack/cinder