py3: suppress the output of open() using `and None`
This patch suppresses the output of open() on Python 3 as it does not return any
output on Python 2.
This makes test-diffstat.t pass on Python 3.5
Differential Revision: https://phab.mercurial-scm.org/D3128
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: ForIndentation
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
IncludeCategories:
- Regex: '^<'
Priority: 1
- Regex: '^"'
Priority: 2