call virtualenv scripts to avoid early exit for windows CI scripts

.gitlab-ci.yml

@@ -8,13 +8,16 @@ build-3.6-VS2017:
     build
   tags:
     - VS2017
+  variables:
+    BUILD_PLATFORM: "VS2017"
+    ARCHITECTURE: "x64"
   before_script:
     - git submodule sync --recursive
     - git submodule update --init --recursive
   script:
     - set Path=%Path%;C:\Program Files\Python36;C:\Program Files\Python36\Scripts;
     - virtualenv --clear -p "C:\Program Files\Python36\python.exe" .
-    - .\Scripts\activate
+    - call .\Scripts\activate
     - python setup.py bdist_wheel --dist-dir dist3
   artifacts:
     paths:
@@ -92,7 +95,7 @@ test-3.6-VS2017:
   script:
     - set Path=%Path%;C:\Program Files\Python36;C:\Program Files\Python36\Scripts;
     - virtualenv --clear -p "C:\Program Files\Python36\python.exe" .
-    - .\Scripts\activate
+    - call .\Scripts\activate
     - cd dist3
     - FOR %wheel in (*.whl) DO pip install %wheel
     - cd ..\tests