There is a bug when deleting a VRF that is the target in a next-hop-vrf.
Steps to reproduce
1: Create VRF
```
set vrf name Red table 10000
set vrf name Blue table 10001
```
2: Add interfaces
```
set interfaces dummy dum10000 address 2001:470:dd54:F0A::1/64
set interfaces dummy dum10000 vrf Red
set interfaces dummy dum10001 address 2001:470:dd54:F0B::1/64
set interfaces dummy dum10001 vrf Blue
```
3: Add Inter-VRF route from Red to Blue
```
set protocols vrf Red static route6 ::/0 next-hop 2001:470:dd54:F0A::2 interface dum10001
```
4: Delete interfaces
```
delete interfaces dummy dum10000
delete interfaces dummy dum10001
```
5: Delete VRF Blue
```
delete vrf name Blue
```
6: Create VRF Blue again
```
create vrf name Blue
```
returns
```
[ vrf ]
RTNETLINK answers: File exists
Error changing VRF: Command '['ip', '-4', 'route', 'add', 'vrf', 'Blue', 'unreachable', 'default', 'metric', '4278198272']' returned non-zero exit status 2.
[[vrf]] failed
Commit failed
```
7: Delete Inter-VRF route from Red to Blue
```
delete protocols vrf Red
```
returns
```
vyos@v6-router-one# delete protocols vrf Red
[edit]
vyos@v6-router-one# commit
[ protocols vrf Red static route6 ::/0 next-hop 2001:470:dd54:F0A::2 ]
% Command incomplete: no
delete [ protocols vrf Red static route6 ::/0 ] failed
delete [ protocols vrf Red static ] failed
[[]] failed
Commit failed
```