cleanupnodes: preserve phase of parents of new nodes As Yuya noted in the review of D3818, passing in targetphase=phases.draft would result in advancing the phase boundary of a secret-phase parent. We never pass targetphase=phases.draft so far, but it's a bug waiting to happen. I tried to refactor it so max(parentphase, X) happened in one place, but I couldn't come up with good variables names and I ended up with a "newphase = max(newphase, parentphase)" line, which made the whole block not look any better to me. Differential Revision: https://phab.mercurial-scm.org/D3824