message: test: braces around gRPC slices
  Fixes a local -Wmissing-braces warning
  Risk Level: n/a (test only)
  Testing: n/a
  Docs Changes: n/a
  Release Notes: n/a
diff: @@ -33,8 +33,8 @@ TEST(GoogleGrpcUtilsTest, MakeBufferInstance1) {
  // Test building a Buffer::Instance from 3 grpc::Slice(s).
  TEST(GoogleGrpcUtilsTest, MakeBufferInstance3) {
  - std::array<grpc::Slice, 3> slices = {grpc::string("test"), grpc::string(" "),
  - grpc::string("this")};
  + std::array<grpc::Slice, 3> slices = {
  + {grpc::string("test"), grpc::string(" "), grpc::string("this")}};
  grpc::ByteBuffer byte_buffer(&slices[0], 3);
  auto buffer_instance = GoogleGrpcUtils::makeBufferInstance(byte_buffer);
  EXPECT_EQ(buffer_instance->toString(), "test this");
  @@ -74,8 +74,8 @@ TEST(GoogleGrpcUtilsTest, MakeByteBuffer3) {
  // Test building a Buffer::Instance from a grpc::ByteBuffer from a Bufffer::Instance with 3 slices.
  TEST(GoogleGrpcUtilsTest, ByteBufferInstanceRoundTrip) {
  - std::array<grpc::Slice, 3> slices = {grpc::string("test"), grpc::string(" "),
  - grpc::string("this")};
  + std::array<grpc::Slice, 3> slices = {
  + {grpc::string("test"), grpc::string(" "), grpc::string("this")}};
  grpc::ByteBuffer byte_buffer(&slices[0], 3);
  auto buffer_instance1 = GoogleGrpcUtils::makeBufferInstance(byte_buffer);
  auto byte_buffer2 = GoogleGrpcUtils::makeByteBuffer(std::move(buffer_instance1));
  