Use the <wsutil/ws_diag_control.h> stuff to disable -Wdeprecated-declarations.

Change-Id: I4b1fcbf5b25f2515d45015c9e1c4a94d6cfbc79c
Reviewed-on: https://code.wireshark.org/review/3883
Reviewed-by: Guy Harris <guy@alum.mit.edu>