Allow CTFMERGE_TERMINATE_NO_UNLINK=1 to keep the output file

--- cddl/contrib/opensolaris/tools/ctf/cvt/ctfmerge.c.orig	Wed Aug 31 14:24:43 2016
+++ cddl/contrib/opensolaris/tools/ctf/cvt/ctfmerge.c	Thu Oct 20 13:31:21 2016
@@ -603,12 +603,10 @@ terminate_cleanup(void)
 	if (outfile == NULL)
 		return;
 
-#if !defined(__FreeBSD__)
 	if (dounlink) {
 		fprintf(stderr, "Removing %s\n", outfile);
 		unlink(outfile);
 	}
-#endif
 }
 
 static void
