dirstate: make a conditionnal easier to read in `setparents`
By grabing `nullid` in the local space, we get the conditionnal to fit in one
line.
Differential Revision: https://phab.mercurial-scm.org/D11427
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: ForIndentation
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
IncludeCategories:
- Regex: '^<'
Priority: 1
- Regex: '^"'
Priority: 2