fix forgotten VCL_INT limits
fix forgotten VCL_INT limits

we missed to change these when we changed the VCL_INT typedef from long
to int64_t

Should we add VCL_INT_MAX / VCL_INT_MIN (and for the other integer
types, respectively)?

gquintard/Varnish-Cache,gquintard/Varnish-Cache,gquintard/Varnish-Cache,gquintard/Varnish-Cache