Bug 1480875 - Only run geckoview-junit ccov on mozilla-central. r=marco

MozReview-Commit-ID: By7cC9wip3i

--HG--
extra : rebase_source : 379e8b609ceb07071fde1d3812e22b9a40b544a5

taskcluster/ci/build/android.yml

@@ -94,6 +94,7 @@ android-api-16-ccov/debug:
         secrets: true
         custom-build-variant-cfg: api-16-debug-ccov
         tooltool-downloads: internal
+    run-on-projects: ['mozilla-central']
     toolchains:
         - android-gradle-dependencies
         - android-ndk-linux