Add license information to the copyright information.

See

	http://www.gnu.org/prep/standards/html_node/_002d_002dversion.html

Change-Id: I19c1cf560a1bb7ed7d7312bea727550977d66120
Reviewed-on: https://code.wireshark.org/review/2787
Reviewed-by: Guy Harris <guy@alum.mit.edu>