Editor crashes When exiting VR mode if the command "hmddbg showcamera on" was used

If the user inputs the command "hmddbg showcamera on" via a command line input then the editor will crash when exiting out of VR Mode.

1. Open the editor
2. Make sure the oculus is hooked up and turned on
3. Click VR preview
4. Press the '~' key
5. Type in the command "hmddbg showcamera on" and hit enter
6. Exit VR mode
7. Notice the Editor crashes

Expected: The command does not cause the editor to crash
Result: Editor crashes upon exiting VR mode

MachineId:E74C21034048BDD873CC6C9A3913CF6C
EpicAccountId:ccbf39de6f9245c0aa23f8e57cc8a566

Access violation - code c0000005 (first/second chance not available)

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UE4Editor_Core!FRotator::Quaternion() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\math\unrealmath.cpp:304]
UE4Editor_OculusRift!FHeadMountedDisplay::DrawDebugTrackingCameraFrustum()
UE4Editor_OculusRift!FOculusRiftHMD::DrawDebug()
UE4Editor_Engine!UGameViewportClient::Draw() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\gameviewportclient.cpp:1215]
UE4Editor_Engine!FViewport::Draw() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\unrealclient.cpp:1001]
UE4Editor_Engine!FSceneViewport::ResizeViewport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\slate\sceneviewport.cpp:1058]
UE4Editor_Engine!FSceneViewport::SetViewportSize() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\slate\sceneviewport.cpp:1012]
UE4Editor_OculusRift!FOculusRiftHMD::DoEnableStereo()
UE4Editor_OculusRift!FOculusRiftHMD::OnEndPlay()
UE4Editor_UnrealEd!UEditorEngine::EndPlayMap() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\playlevel.cpp:81]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\editorengine.cpp:973]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\unrealedengine.cpp:366]
UE4Editor!FEngineLoop::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\launchengineloop.cpp:2359]
UE4Editor!GuardedMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]