message: spare drives filtering fix
diff: </cs-top-bar>
  <div *ngIf="selectedZones?.length" cs-list>
  - <div class="section" *ngFor="let s of sections">
  + <ng-container *ngFor="let s of sections">
  + <div class="section" *ngIf="s?.spareDrives?.length">
  <h4 class="section-header">{{ s.zoneName }}</h4>
  <cs-spare-drive-list
  *loading="!volumes"
  cs-list
  ></cs-spare-drive-list>
  </div>
  + </ng-container>
  </div>
  <div *ngIf="!selectedZones || !selectedZones.length" cs-list>
  