Merge pull request dotnet/coreclr#6772 from mellinoe/fix-build-packages

Specify packages.builds by default in build-packages command

Commit migrated from https://github.com/dotnet/coreclr/commit/a4e5efceace0e173b258cb9c8a54fce4292c10d4

diff --cc src/coreclr/config.json
index 3a73eed,8cd0f70..1ddb2f9
--- 1/src/coreclr/config.json
--- 2/src/coreclr/config.json
+++ b/src/coreclr/config.json
@@@ -471,9 -495,12 +471,10 @@@
        "defaultValues": {
          "toolName": "msbuild",
          "settings": {
 -          "MsBuildParameters": "default",
            "__BuildOS": "default",
 -          "maxcpucount": "default",
            "MsBuildFileLogging": "/flp:v=detailed;Append;LogFile=build-packages.log",
-           "MsBuildEventLogging": "default"
+           "MsBuildEventLogging": "default",
+           "Project": "src/.nuget/packages.builds"
          }
        }
      }