www/varnish-modules: fix build on GCC architectures

cc1: warnings being treated as errors
vmod_bodyaccess.c: In function 'vmod_hash_req_body':
vmod_bodyaccess.c:205: warning: 'VSB_delete' is deprecated (declared at /usr/local/include/varnish/vsb.h:79)
vmod_bodyaccess.c: In function 'vmod_rematch_req_body':
vmod_bodyaccess.c:278: warning: 'VSB_delete' is deprecated (declared at /usr/local/include/varnish/vsb.h:79)