release-post.js script should ignore PPC BE 64-bit Binary

[targos]

Similar to #1769

PPC BE is not supported above Node 8: https://github.com/nodejs/build/blob/060809a571c133da35051136023ec19006a275a7/jenkins/scripts/VersionSelectorScript.groovy#L49-L50

[mhdawson]

I assume it still needs to support PPC BE for 6.x releases, right?

[targos]

I assume it still needs to support PPC BE for 6.x releases, right?

Yes

Fixed at #1819.