revert clang r331746 to r328903 (#75)

* clang r331746 failed on some of the tests and may not be stable.
  Revert to the last stable revision r328903
diff --git a/WORKSPACE b/WORKSPACE
index a92b725..ca05153 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -57,16 +57,18 @@
     repository = "cloud-marketplace/google/ubuntu16_04",
 )
 
+# gcr.io/cloud-marketplace/google/clang-debian8:r328903
 container_pull(
     name = "debian8-clang",
-    digest = "sha256:c85ca4729d378ffde330376f2314fb3e0c99ef94d48207cfc11add34741dc8b7",
+    digest = "sha256:8bb65bf0a0da8be48bbac07ebe743805f3dc5259203e19517098162bd23a768f",
     registry = "gcr.io",
     repository = "cloud-marketplace/google/clang-debian8",
 )
 
+# gcr.io/cloud-marketplace/google/clang-ubuntu:r328903
 container_pull(
     name = "ubuntu16_04-clang",
-    digest = "sha256:be5ce2e9d779b94195656be4c7a998a93a29067fb921a9bda97bf99a034a18d3",
+    digest = "sha256:d553634f23f7c437ca35bbc4b6f1f38bb81be32b9ef2df4329dcd36762277bf7",
     registry = "gcr.io",
     repository = "cloud-marketplace/google/clang-ubuntu",
 )
diff --git a/third_party/clang/revision.bzl b/third_party/clang/revision.bzl
index b71b4bf..6551eac 100644
--- a/third_party/clang/revision.bzl
+++ b/third_party/clang/revision.bzl
@@ -1,7 +1,7 @@
-CLANG_REVISION = "r331746"
+CLANG_REVISION = "r328903"
 
-DEBIAN8_CLANG_SHA256 = "a80dcc2477c32c728a2b9e84b56ef340da3c15b362dfeb7b5cd8d77a291f0547"
+DEBIAN8_CLANG_SHA256 = "8f460b909788ffd8dd467ea4ee106ccd08b4a43408dd98ac8e3938a9b6452bb7"
 
-DEBIAN9_CLANG_SHA256 = "4d275f7f3c0ab57af4d8d8d23f4525f5adb95d55af54aae719787b63f515edf4"
+DEBIAN9_CLANG_SHA256 = "350f77999033e39a02294406250df819cacb2106daa7b04b5fd6bfe7aa0ab5a1"
 
-UBUNTU16_04_CLANG_SHA256 = "71586e03c50665aa06f379ff29d3872ee56cbc3b7c06385544875fbfec166519"
+UBUNTU16_04_CLANG_SHA256 = "f1874c57aa1e34c09595a4a0e03b91d7bf89dd7ad044ff4834b46198ff2e9d14"
diff --git a/third_party/libcxx/revision.bzl b/third_party/libcxx/revision.bzl
index 2522903..9d34c97 100644
--- a/third_party/libcxx/revision.bzl
+++ b/third_party/libcxx/revision.bzl
@@ -1,7 +1,7 @@
-LIBCXX_REVISION = "r331746"
+LIBCXX_REVISION = "r328903"
 
-DEBIAN8_LIBCXX_SHA256 = "b95ac75fbe33a1d1e4d7ae6ebe00580f99eb94928ad9a7d16395abb2921e7070"
+DEBIAN8_LIBCXX_SHA256 = "d9798333832690577ca740acb3016a803be684ad0ed02e78922424b4b651f8ce"
 
-DEBIAN9_LIBCXX_SHA256 = "c129082e5024fd2dcd5738d54d8b2a7ee4231b4e0981de43fe91ab921af07fcc"
+DEBIAN9_LIBCXX_SHA256 = "66219b838f8d243c071a4c094e13ef78082cd858d87841dd607839a351680b90"
 
-UBUNTU16_04_LIBCXX_SHA256 = "d0b65d2b63fff7599a4a1bd0844041359e8f7f0d17145cabe7a1045b6a9a8dda"
+UBUNTU16_04_LIBCXX_SHA256 = "786a35a813e493342a018c04b8fb951a8b34a7d7e377e1ac793db738fc240451"