Online DDL: fix defer function, potential connection pool exhaustion … #425

Job	Run time
Build and push lite (latest)	4m 16s
Build and push vttestserver (mysql80)	2m 34s
Build and push lite (percona80)	4m 19s
Build and push (bullseye, vtadmin)	1m 13s
Build and push (bullseye, vtorc)	1m 9s
Build and push (bullseye, vtgate)	49s
Build and push (bullseye, vttablet)	40s
Build and push (bullseye, mysqlctld)	47s
Build and push (bullseye, mysqlctl)	47s
Build and push (bullseye, vtctl)	1m 2s
Build and push (bullseye, vtctlclient)	46s
Build and push (bullseye, vtctld)	1m 37s
Build and push (bullseye, vtctldclient)	44s
Build and push (bullseye, logrotate)	33s
Build and push (bullseye, logtail)	41s
Build and push (bullseye, vtbackup)	55s
Build and push (bullseye, vtexplain)	45s
Build and push (bookworm, vtadmin)	1m 21s
Build and push (bookworm, vtorc)	58s
Build and push (bookworm, vtgate)	54s
Build and push (bookworm, vttablet)	52s
Build and push (bookworm, mysqlctld)	47s
Build and push (bookworm, mysqlctl)	44s
Build and push (bookworm, vtctl)	1m 10s
Build and push (bookworm, vtctlclient)	40s
Build and push (bookworm, vtctld)	1m 36s
Build and push (bookworm, vtctldclient)	58s
Build and push (bookworm, logrotate)	40s
Build and push (bookworm, logtail)	39s
Build and push (bookworm, vtbackup)	48s
Build and push (bookworm, vtexplain)	45s
Slack Notification if failed	0s
	36m 29s

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