Log Message:
adwaita-icon-theme: update to 3.26.0.

3.26.0
  - thunderbolt status icons
  - system settings icons

3.25.91
  - rendering fixes
  - system settings icons (bug #786605)
  - tab (bug #786651)
  - display settings icons

3.25.4
  - symbolic firmware and device icon
  - form validation error icon (symbolic)
  - fullcolor emblem fixes
  - symbolic icon for pinning views