Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/src/google/protobuf/compiler/ruby/ruby_generator.h

Index: third_party/protobuf/src/google/protobuf/compiler/ruby/ruby_generator.h
diff --git a/third_party/protobuf/src/google/protobuf/compiler/ruby/ruby_generator.h b/third_party/protobuf/src/google/protobuf/compiler/ruby/ruby_generator.h
index 8c1dfa26717296275db5233698aacca0ef312f51..75555c31b59917ea5630361e39cefa3a314eb99d 100644
--- a/third_party/protobuf/src/google/protobuf/compiler/ruby/ruby_generator.h
+++ b/third_party/protobuf/src/google/protobuf/compiler/ruby/ruby_generator.h
@@ -28,8 +28,6 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Generates Ruby code for a given .proto file.
-
 #ifndef GOOGLE_PROTOBUF_COMPILER_RUBY_GENERATOR_H__
 #define GOOGLE_PROTOBUF_COMPILER_RUBY_GENERATOR_H__
 
@@ -42,10 +40,6 @@ namespace protobuf {
 namespace compiler {
 namespace ruby {
 
-// CodeGenerator implementation for generated Ruby protocol buffer classes.
-// If you create your own protocol compiler binary and you want it to support
-// Ruby output, you can do so by registering an instance of this
-// CodeGenerator with the CommandLineInterface in your main() function.
 class LIBPROTOC_EXPORT Generator
     : public google::protobuf::compiler::CodeGenerator {
   virtual bool Generate(