LICENSE: add a statement about the ownership of protoc-c output
LICENSE: add a statement about the ownership of protoc-c output

Signed-off-by: Dave Benson <4cfeb550c2256ab1b54dac95cf722dd300951a19@gmail.com>

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