Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/src/google/protobuf/message.cc

Index: third_party/protobuf/src/google/protobuf/message.cc
diff --git a/third_party/protobuf/src/google/protobuf/message.cc b/third_party/protobuf/src/google/protobuf/message.cc
index 032748bdaa8b3e4674892de5840c5bcc6eca331c..d62ca79c80cb7d49cdf4a2dc814db293560f5f81 100644
--- a/third_party/protobuf/src/google/protobuf/message.cc
+++ b/third_party/protobuf/src/google/protobuf/message.cc
@@ -69,7 +69,7 @@ void Message::MergeFrom(const Message& from) {
   GOOGLE_CHECK_EQ(from.GetDescriptor(), descriptor)
     << ": Tried to merge from a message with a different type.  "
        "to: " << descriptor->full_name() << ", "
-       "from:" << from.GetDescriptor()->full_name();
+       "from: " << from.GetDescriptor()->full_name();
   ReflectionOps::Merge(from, this);
 }
 
@@ -82,7 +82,7 @@ void Message::CopyFrom(const Message& from) {
   GOOGLE_CHECK_EQ(from.GetDescriptor(), descriptor)
     << ": Tried to copy from a message with a different type. "
        "to: " << descriptor->full_name() << ", "
-       "from:" << from.GetDescriptor()->full_name();
+       "from: " << from.GetDescriptor()->full_name();
   ReflectionOps::Copy(from, this);
 }