gitlab-ci: update Piglit commit, update skips

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 895017a..b8646f7 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -15,7 +15,7 @@
 variables:
   UPSTREAM_REPO: mesa/mesa
   DEBIAN_TAG: "amd64-2019-11-13-2"
-  DEBIAN_TEST_TAG: "amd64-test-2019-11-12-2"
+  DEBIAN_TEST_TAG: "amd64-test-2019-11-15"
   DEBIAN_ARM64_TAG: "arm64v8-2019-11-13"
   DEBIAN_ARM64_TEST_TAG: "arm64v8-test-2019-11-12-2"
   STRETCH_TAG: "2019-09-18"