To reproduce:
1. Open attached project;
2. Open "test" scene;
3. In the Game window, select Display 2;
4. Choose Main Camera and disable HDR in the Inspector;
5. Enter Play mode.

Expected result: no crash in the Editor when HDR is disabled and Display 1 is not selected.
Actual result: crash in the Editor when HDR is disabled and Display 1 is not selected.

Note: Editor does not crash if 3rd OR 4th steps are skipped.

Reproduced with Oculus Rift DK2.

Reproduced on versions: 5.6.0f2, 5.6.0p1, 2017.1.0b1.
Not reproduced on versions: 5.6.0f1, 2017.1.0a6.
Regression introduced on versions: 5.6.0f2, 2017.1.0b1.