[469b] Failed delete actors in some cases

[SeriousBuggie]

Reproduce:

1. Start UnrealEd.
2. Open MH-GladiatorV0_11.zip
3. Try delete any MHGSpot.

Expected result: Actor deleted.
Actual result: crash:

History: EndState <- ULevel::DestroyActor <- (MHGSpot MyLevel.MHGSpot11082) <- 
UEditorEngine::edactDeleteSelected <- UEditorEngine::Exec <- (ACTOR DELETE)
SE(C0000005) @ 0F24DDA6
fl=0 rec=0 n=37214764 i[0]=0 i[1]=3f0
eax=00000000 ebx=109d5338 ecx=2d5fb99c edx=0f3186f4 esi=2d5fb99c edi=109d530c eip=0f24dda6
ebp=0237dee0 esp=0237dee0 cs=0023 ds=002b es=002b fs=0053 gs=002b flags=00010246
 <- WEditorFrame::OnCommand <- WM_COMMAND

[SeriousBuggie]

Workaround:

• not try delete,
• select all actors for delete,
• send to last,
• export to t3d,
• start new map,
• edit t3d with text editor - delete last actors.
• import t3d
• build map.

[SeriousBuggie]

Duplicate of #1400