Rename getdate.c to getdate.c.cvs, since the "normal" build procedure do

imply that yacc/bison exists and can generate this file. Those without one
of those tools can then checkout and rename the getdate.c.cvs file.

diff --git a/lib/getdate.c b/lib/getdate.c.cvs
similarity index 100%
rename from lib/getdate.c
rename to lib/getdate.c.cvs