Martin von Zweigbergk <martinvonz@google.com> [Sat, 09 Mar 2019 22:11:27 -0800] rev 42409
merge: reorder some initialization to make more sense
This puts the closely related definitions of "pl", "p1", "p2", "pas"
close together, and moves the definition of "overwrite" away and
closer to where it's first used.
Differential Revision: https://phab.mercurial-scm.org/D6471