rebase: register status file generator only once when using single transaction
rebase.storestatus() behaved differently depending on whether a
transaction is passed to it. If a transaction is passed, it registers
a "file generator" that runs when the transaction commits. If no
transaction was passed, it writes the rebase state immediately. This
imprecise timing of the writing makes it hard to reason about, so
let's make it more explicit which behavior we're getting by checking
if we have a transaction before calling it. For the single-transaction
case, move the call to storestatus(tr) early and do it only once since
it's only going to write the file (at most) once anyway.
Differential Revision: https://phab.mercurial-scm.org/D2912
<Include>
<?if $(var.Platform) = "x64" ?>
<?define IsX64 = yes ?>
<?else?>
<?define IsX64 = no ?>
<?endif?>
</Include>