fix continuous build

build/tfs/build.yml

@@ -1,9 +1,11 @@
-variables:
-  VSCODE_BUILD_VERBOSE: true
-  System.Debug: true
-
 phases:
 - phase: Windows
+  queue: Hosted VS2017
+  variables:
+    VSCODE_BUILD_VERBOSE: true
+    System.Debug: true
+
+  steps:
   - task: NodeTool@0
     inputs:
       versionSpec: "8.9.1"
@@ -25,6 +27,12 @@ phases:
     name: test
 
 - phase: Linux
+  queue: Hosted Linux Preview
+  variables:
+    VSCODE_BUILD_VERBOSE: true
+    System.Debug: true
+
+  steps:
   - script: |
       apt-get update
       apt-get install -y libxkbfile-dev pkg-config libsecret-1-dev libxss1 libgconf-2-4 dbus xvfb
@@ -54,6 +62,9 @@ phases:
 
 - phase: macOS
   queue: Hosted macOS Preview
+  variables:
+    VSCODE_BUILD_VERBOSE: true
+    System.Debug: true
   steps:
 
   - task: NodeTool@0