V Editor Toolset > Renderer Wireframe
Selecting any object on the scene with Renderer component attached will always show its mesh wireframe. Wireframe rendering could be switched with this utility.
- Select one or more scene objects with any Renderer component attached
- Go to V Editor Toolset Quick Access Menu (Ctrl + Alt + V) and click Hide. From now on the wireframe will be hidden for selected renderers. Click Show for viсe versa
Starting from Unity 5.5 there are built-in way to hide renderer wireframe trough the Gizmos menu