Extract to /usr/local/filtron/local

The /usr/local/filtron/local/go directory will be created by tar.

docs/build-templates/filtron.rst

@@ -32,7 +32,7 @@
        (${SERVICE_USER}) $ mkdir ${SERVICE_HOME}/local
        (${SERVICE_USER}) $ wget --progress=bar -O "${GO_TAR}" \\
                    "${GO_PKG_URL}"
-       (${SERVICE_USER}) $ tar -C ${SERVICE_HOME}/local/go -xzf "${GO_TAR}"
+       (${SERVICE_USER}) $ tar -C ${SERVICE_HOME}/local -xzf "${GO_TAR}"
        (${SERVICE_USER}) $ which go
        ${SERVICE_HOME}/local/go/bin/go