Use vs2017-15.4.5 for AppVeyor

Update to libcc with VS2017 15.4.5

DEPS

@@ -2,7 +2,7 @@ vars = {
   'chromium_version':
     '63.0.3239.150',
   'libchromiumcontent_revision':
-    '1c542968990da951df27c8a0371a4ab5494a5a6c',
+    'a81166ad79e68fbfe7cf5ba243192d6412e26b37',
   'node_version':
     'v9.7.0-33-g538a5023af',
   'native_mate_revision':

appveyor-override.yml

@@ -1,13 +1,11 @@
-version: 1.0.{build}
-branches:
-  except:
-  - /^release$|^release-\d-\d-x$/
 build_cloud: electron-16
-image: electron-16-vs2017
-environment:
-  DISABLE_CRASH_REPORTER_TESTS: true
+image: electron-16-vs2017-15.4.5
 build_script:
 - ps: >-
+    echo "Build worker image $env:APPVEYOR_BUILD_WORKER_IMAGE"
+
+    &"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe"
+
     if(($env:APPVEYOR_PULL_REQUEST_HEAD_REPO_NAME -split "/")[0] -eq ($env:APPVEYOR_REPO_NAME -split "/")[0]) {
       Write-warning "Skipping PR build for branch"; Exit-AppveyorBuild
     } else {

vendor/libchromiumcontent

@@ -1 +1 @@
-Subproject commit 0106aa2d014dc1cf1f08b1567b65f5af8992f99a
+Subproject commit a81166ad79e68fbfe7cf5ba243192d6412e26b37