Ignore failures during pre-start
Ignore failures during pre-start

- this is because the rejoin-unsafe errand currently only works on nodes that have
  a galera-healthcheck process running; this will not be the case for nodes
  that have failed to pre-start.

[#131014785]

Signed-off-by: Aaron Hurley <6c541e38cb40b4360b80e64c308405691f38e38a@pivotal.io>

cloudfoundry/cf-mysql-release,cloudfoundry/cf-mysql-release,cloudfoundry/cf-mysql-release,cloudfoundry/cf-mysql-release