Fix spellcheck problem (boostrap ==> bootstrap) #5738

Job	Run time
build / Build	10m 50s
Integration Tests (certrotation)	1m 27s
Integration Tests (etcdrestore)	2m 20s
Integration Tests (localstorage)	1m 15s
Integration Tests (startup)	7m 45s
Integration Tests (custometcdargs)	36s
Integration Tests (etcdsnapshot)	7m 50s
Integration Tests (kubeflags)	7m 12s
Integration Tests (longhorn)	2m 53s
Integration Tests (secretsencryption)	3m 10s
	45m 18s

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