protobuf-c: rename protobuf_c_message_init_generic() and update the TODO comment
protobuf-c: rename protobuf_c_message_init_generic() and update the TODO comment

this function is now static, so it shouldn't have the "protobuf_c_"
prefix in its name.

koolhazz/protobuf-c,koolhazz/protobuf-c,koolhazz/protobuf-c,pepsi7959/protobuf-c,y12uc231/protobuf-c,hongbinz/protobuf-c,Sannis/protobuf-c,Sannis/protobuf-c,Sannis/protobuf-c,tutu12777/protobuf-c,y12uc231/protobuf-c,lanniaoershi/protobuf-c,y12uc231/protobuf-c,pepsi7959/protobuf-c,virqin/protobuf-c,lanniaoershi/protobuf-c,virqin/protobuf-c,hongbinz/protobuf-c,lanniaoershi/protobuf-c,virqin/protobuf-c,tutu12777/protobuf-c,tutu12777/protobuf-c,hongbinz/protobuf-c,pepsi7959/protobuf-c