contributed DLZ drivers fail to compile in 9.8.1

Greetings,

I introduced (and somehow failed to notice, oops) a build failure in 9.8.1
when using contributed DLZ drivers (mysql, postgresql, etc).  It'll be
fixed in 9.8.2, and in the meantime here's a patch:

Index: contrib/dlz/drivers/sdlz_helper.c
===================================================================
RCS file: /proj/cvs/prod/bind9/contrib/dlz/drivers/sdlz_helper.c,v
retrieving revision 1.3
diff -u -r1.3 sdlz_helper.c
--- contrib/dlz/drivers/sdlz_helper.c	14 May 2010 06:29:37 -0000	1.3
+++ contrib/dlz/drivers/sdlz_helper.c	5 Sep 2011 17:31:30 -0000
 <at>  <at>  -50,8 +50,6  <at>  <at> 
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */

-#ifdef DLZ
-
 #include <config.h>

 #include <dns/log.h>
 <at>  <at>  -527,5 +525,3  <at>  <at> 

 	return isc_mem_strdup(mctx, value);
 }
-
-#endif