third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/ruby/lib/google/protobuf/repeated_field.rb

Index: third_party/protobuf/ruby/lib/google/protobuf/repeated_field.rb
diff --git a/third_party/protobuf/ruby/lib/google/protobuf/repeated_field.rb b/third_party/protobuf/ruby/lib/google/protobuf/repeated_field.rb
index 0ad2060d433293defe4d281b813714c5021a1286..831e0320dd20e18d84f5bf4adecc21022ebe1be7 100644
--- a/third_party/protobuf/ruby/lib/google/protobuf/repeated_field.rb
+++ b/third_party/protobuf/ruby/lib/google/protobuf/repeated_field.rb
@@ -173,7 +173,7 @@ module Google
           external_enumerator.each_with_index do |val, i|
             result = yield(val)
             results << result
-            #nil means no change occured from yield; usually occurs when #to_a is called
+            #nil means no change occurred from yield; usually occurs when #to_a is called
             if result
               repeated_field[i] = result if result != val
             end