Fix typo that prevents successful compilation

ldap/pool.go

@@ -188,7 +188,7 @@ func (p *ConnectionPool) doRequest(ctx context.Context, name string, attrs []tra
 	// Tracing: set the final status.
 	span.SetStatus(errorToTraceStatus(rerr))
 	requestsCounter.WithLabelValues(name).Inc()
-	if err != nil {
+	if rerr != nil {
 		requestErrors.WithLabelValues(name).Inc()
 	}
 
@@ -293,3 +293,12 @@ var (
 		Help: "Counter of LDAP requests.",
 	}, []string{"method"})
 )
+
+func init() {
+	prometheus.MustRegister(
+		connectionsCounter,
+		connectionErrors,
+		requestsCounter,
+		requestErrors,
+	)
+}