Npcap 0.96 crashes with REFERENCE_BY_POINTER in NPF_ReleaseOpenInstanceResources

Call stack:

```
nt!KeBugCheckEx
nt!ObfDereferenceObject+0x15eba3
npcap!NPF_ReleaseOpenInstanceResources+0x6b [Openclos.c @ 544]
npcap!NPF_Cleanup+0x4b [Openclos.c @ 975]
nt!IofCallDriver
nt!IopCloseFile
nt!ObCloseHandleTableEntry
nt!NtClose
nt!KiSystemServiceCopyEnd
```