VS: Fix .vcxproj indentation

In commit v3.8.0-rc1~87^2~1 (VS: added support for C#, 2017-01-09) we
removed what looked like a no-op streaming operation but in fact it
is responsible for applying indentation.  Restore the line.
67 jobs for vcxproj-indentation
Status Job ID Name Coverage
  External
passed cdash

passed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-release-vs2015

passed ghostflow-branch-check

passed ghostflow-commit-check

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

failed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-debug-vs2015

00:30:58

failed cmake-dash3win7-windows-debug-vs2015

passed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

failed cmake-dash3win7-windows-release-vs2015

passed cmake-dash3win7-windows-release-vs2015

passed cmake-dash3win7-windows-release-vs2015

passed cmake-dash3win7-windows-release-vs2015

passed cmake-dash3win7-windows-release-vs2015

00:23:10

failed cmake-dash3win7-windows-release-vs2015