Fix nginx comilation error

To avoid stopping bosh with the error:
<pre>
src/core/ngx_resolver.c: In function ‘ngx_resolver_process_ptr’:
src/core/ngx_resolver.c:1425:43: error: variable ‘qclass’ set but not used [-Werror=unused-but-set-variable]
src/core/ngx_resolver.c:1425:36: error: variable ‘qtype’ set but not used [-Werror=unused-but-set-variable]
cc1: all warnings being treated as errors
</pre>
on compilation of nginx.