required protobuf version above what is required by configure

With protobuf-2.0.3 (the minimum required by ./configure)

 g++ -DHAVE_CONFIG_H -I. -I. -ggdb3 -I/home/peter/builds/libdrizzle/include -pthread -pipe -O3 -Werror -pedantic -Wall -Wextra -Wundef -Wshadow -fdiagnostics-show-option -fvisibility=hidden -Wformat -fno-strict-aliasing -Wno-strict-aliasing -Woverloaded-virtual -Wnon-virtual-dtor -Wctor-dtor-privacy -Wno-long-long -Wno-redundant-decls -Wno-attributes -std=gnu++98 -MT plugin/transaction_log/plugin_libtransaction_log_plugin_la-transaction_log.lo -MD -MP -MF plugin/transaction_log/.deps/plugin_libtransaction_log_plugin_la-transaction_log.Tpo -c plugin/transaction_log/transaction_log.cc -fPIC -DPIC -o plugin/transaction_log/.libs/plugin_libtransaction_log_plugin_la-transaction_log.o
plugin/transaction_log/transaction_log.cc: In member function ‘virtual void TransactionLog::apply(const drizzled::message::Transaction&)’:
plugin/transaction_log/transaction_log.cc:193: error: ‘WriteLittleEndian32ToArray’ is not a member of ‘google::protobuf::io::CodedOutputStream’
plugin/transaction_log/transaction_log.cc:194: error: ‘WriteLittleEndian32ToArray’ is not a member of ‘google::protobuf::io::CodedOutputStream’
plugin/transaction_log/transaction_log.cc:200: error: ‘const class drizzled::message::Transaction’ has no member named ‘SerializeWithCachedSizesToArray’
plugin/transaction_log/transaction_log.cc:209: error: ‘WriteLittleEndian32ToArray’ is not a member of ‘google::protobuf::io::CodedOutputStream’
make[2]: *** [plugin/transaction_log/plugin_libtransaction_log_plugin_la-transaction_log.lo] Error 1

WriteLittleEndian32ToArray is available in 2.1.0.

Pete