Revert "Temporarily restrict set of sites to zh.wikipedia.org and zh.…

…wikiquote.org"

This reverts commit 6abd161.

It was a one-off  experiment, trying to find the cause of a bug.
#40

cmd/qrank-builder/itemsignals.go

@@ -167,16 +167,6 @@ func buildItemSignals(ctx context.Context, pageviews []string, sites *map[string
 	}
 	defer compressor.Close()
 
-	// Temporarily restrict the set of sites to zh.wikipedia.org
-	// and zh.wikiquote.org.
-	// TODO: This is just hack to investigate a bug. Remove it.
-	// https://github.com/brawer/wikidata-qrank/issues/40
-	for key, _ := range *sites {
-	    if key != "zhwiki" && key != "zhwikiquote" {
-		   delete(*sites, key)
-		}
-	}
-
 	writer := NewItemSignalsWriter(compressor)
 	scanners := make([]LineScanner, 0, len(pageviews)+1)
 	scannerNames := make([]string, 0, len(pageviews)+1)