build: improved prepare.sh

[ssbarnea]

• assure we use bash strict mode
• avoid shallow errors on full clones
• make script bit more idempotent

Signed-off-by: Sorin Sbarnea [email protected]

[openshift-ci-robot]

Hi @ssbarnea. Thanks for your PR.

I'm waiting for a containers member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[jwhonce]

/ok-to-test

[rhatdan]

LGTM

[TomSweeneyRedHat]

LGTM but definitely want a head nod from @baude or @mheon. Happy green test buttons.

[TomSweeneyRedHat]

/approve

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ssbarnea, TomSweeneyRedHat

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[giuseppe]

/lgtm