sendfile: fix memory access issue wrt boost::tokenizer and its input buffer
sendfile: fix memory access issue wrt boost::tokenizer and its input buffer

we MUST keep the string until end of tokenization we the
boost::tokenizer doesn't seem to make its own copy/representation of the
input buffer.

xzero/x0,christianparpart/x0,xzero/x0,christianparpart/x0,xzero/x0,christianparpart/x0,xzero/x0,christianparpart/x0,christianparpart/x0,christianparpart/x0,xzero/x0,xzero/x0,christianparpart/x0