Add SelectParams to Select for federation

When prom2 came out the storage querier interface consolidated to a
single Select() method. While doing this it makes it impossible as the
implementer of the querier to know if you are being called for metadata
or actual data. The workaround has been to check if the SelectParams are
nil, which the federation call is always nil. This has 2 negative
consequences (1) remote implementations interpret this as a metadata
call, which makes the federation endpoint return nothing. (2) this means
that the storage implementations don't get the same information passed
down to them as far as SelectParams goes.

This diff simply adds SelectParams to the Select() call in the
federation handler

Mitigation for prometheus#4057

Signed-off-by: Thomas Jackson <jacksontj.89@gmail.com>

web/federate.go

@@ -72,9 +72,14 @@ func (h *Handler) federation(w http.ResponseWriter, req *http.Request) {
 
 	vec := make(promql.Vector, 0, 8000)
 
+	params := &storage.SelectParams{
+		Start: mint,
+		End:   maxt,
+	}
+
 	var sets []storage.SeriesSet
 	for _, mset := range matcherSets {
-		s, err := q.Select(nil, mset...)
+		s, err := q.Select(params, mset...)
 		if err != nil {
 			federationErrors.Inc()
 			http.Error(w, err.Error(), http.StatusInternalServerError)