Bug 1386610 - Use the clang 4 toolchain job for fuzzing builds. r=gps

--HG--
extra : rebase_source : 4f9d1a20eb8ed3ef4a74451f0868cb2b10c4d031

browser/config/tooltool-manifests/linux64/fuzzing.manifest

@@ -1,13 +1,4 @@
 [
-  {
-    "version": "clang 4.0.1 gecko build for linux",
-    "size": 215309284,
-    "visibility": "public",
-    "digest": "8f6d386ca1d4606526dd24f366b1dbc1914c6c6d7f54c69c2a2ca0e7cfabe641c1168952d606295feffa9f38ad687084de5efb1e80be3ed2f431ac91de80039b",
-    "algorithm": "sha512",
-    "filename": "clang.tar.xz",
-    "unpack": true
-  },
   {
     "version": "rustc 1.19.0 (0ade33941 2017-07-17) repack",
     "size": 161014632,

taskcluster/ci/build/linux.yml

@@ -421,6 +421,7 @@ linux64-asan-fuzzing/opt:
         tooltool-downloads: public
         need-xvfb: true
     toolchains:
+        - linux64-clang-4
         - linux64-gcc
         - linux64-sccache