Get/MultiGet API with no type provided and doc does not exists causes a failure, closes elastic#1794.

Author: kimchy

modules/elasticsearch/src/main/java/org/elasticsearch/index/get/GetResult.java

@@ -300,7 +300,9 @@ public static GetResult readGetResult(StreamInput in) throws IOException {
 
     @Override public void readFrom(StreamInput in) throws IOException {
         index = in.readUTF();
-        type = in.readUTF();
+        if (in.readBoolean()) {
+            type = in.readUTF();
+        }
         id = in.readUTF();
         version = in.readLong();
         exists = in.readBoolean();
@@ -323,7 +325,12 @@ public static GetResult readGetResult(StreamInput in) throws IOException {
 
     @Override public void writeTo(StreamOutput out) throws IOException {
         out.writeUTF(index);
-        out.writeUTF(type);
+        if (type == null) {
+            out.writeBoolean(false);
+        } else {
+            out.writeBoolean(true);
+            out.writeUTF(type);
+        }
         out.writeUTF(id);
         out.writeLong(version);
         out.writeBoolean(exists);