cmd/pkgsite: remove unnecessary cast
cmd/pkgsite: remove unnecessary cast

Change-Id: I1e7d75d42d6d25a2f9463f01a9a7ca30e8fdf368
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/295169
Reviewed-by: Jonathan Amsterdam <e3d3698b2ccd5955e4adf250d0785062d0f9018b@google.com>
Trust: Jamal Carvalho <e0195770807aa8c82b0b128d9c0423b5ad035172@golang.org>

golang/pkgsite,golang/pkgsite,golang/pkgsite,golang/pkgsite