gnupg-2.0.19: make distclean removes critical file

[Nelson H. F. Beebe]

A "make distclean" operation in gnupg-2.0.19 removes a
critical file: 

make[1]: Entering directory `/export/home/build/bare/gnupg-2.0.19/common'
test -z "audit-events.h status-codes.h" || rm -f audit-events.h status-codes.h

common/audit-events.h is part of the original distribution,
and gnupg-2.0.19 cannot be rebuilt without it.

-------------------------------------------------------------------------------
- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                    FAX: +1 801 581 4148                  -
- Department of Mathematics, 110 LCB    Internet e-mail: beebe at math.utah.edu  -
- 155 S 1400 E RM 233                       beebe at acm.org  beebe at computer.org -
- Salt Lake City, UT 84112-0090, USA    URL: http://www.math.utah.edu/~beebe/ -
-------------------------------------------------------------------------------