Hmm ... It's impossible ;-) This RPM doesn't exist on any FTP server

Provides :
pkgconfig(protobuf)
protobuf-devel
protobuf-devel(x86-32)

Requires :

rpmlib(CompressedFileNames) <= 3.0.4-1
rpmlib(VersionedDependencies) <= 3.0.3-1
/usr/bin/pkg-config
pkgconfig
libprotobuf.so.7
libprotoc.so.7
protobuf-compiler = 2.4.1-1.el6
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
protobuf = 2.4.1-1.el6

Content of RPM :
/usr/include/google
/usr/include/google/protobuf
/usr/include/google/protobuf/compiler
/usr/include/google/protobuf/compiler/code_generator.h
/usr/include/google/protobuf/compiler/command_line_interface.h
/usr/include/google/protobuf/compiler/cpp
/usr/include/google/protobuf/compiler/cpp/cpp_generator.h
/usr/include/google/protobuf/compiler/importer.h
/usr/include/google/protobuf/compiler/java
/usr/include/google/protobuf/compiler/java/java_generator.h
/usr/include/google/protobuf/compiler/parser.h
/usr/include/google/protobuf/compiler/plugin.h
/usr/include/google/protobuf/compiler/plugin.pb.h
/usr/include/google/protobuf/compiler/plugin.proto
/usr/include/google/protobuf/compiler/python
/usr/include/google/protobuf/compiler/python/python_generator.h
/usr/include/google/protobuf/descriptor.h
/usr/include/google/protobuf/descriptor.pb.h
/usr/include/google/protobuf/descriptor.proto
/usr/include/google/protobuf/descriptor_database.h
/usr/include/google/protobuf/dynamic_message.h
/usr/include/google/protobuf/extension_set.h
/usr/include/google/protobuf/generated_message_reflection.h
/usr/include/google/protobuf/generated_message_util.h
/usr/include/google/protobuf/io
/usr/include/google/protobuf/io/coded_stream.h
/usr/include/google/protobuf/io/printer.h
/usr/include/google/protobuf/io/tokenizer.h
/usr/include/google/protobuf/io/zero_copy_stream.h
/usr/include/google/protobuf/io/zero_copy_stream_impl.h
There is 23 files more in these RPM.