Fix buffer overflow in net_writer.c:write_meta().
Fix buffer overflow in net_writer.c:write_meta().

- Use strncpy() on a heap-allocated buffer, instead of
  sprintf() on a stack-allocated buffer.
- Similar to the problem in IssueID #143.


lees0414/EUproject,lees0414/EUproject,mytestbed/oml,mytestbed/oml,alco90/soml,alco90/soml,lees0414/EUproject,alco90/soml,lees0414/EUproject,alco90/soml,mytestbed/oml,lees0414/EUproject,alco90/soml,mytestbed/oml,mytestbed/oml