Bug deleting route-map rule with community list
To reproduce
```
set policy community-list BGP01 rule 10 action 'permit'
set policy community-list BGP01 rule 10 regex '65001'
set policy route-map RMAP rule 30 action 'permit'
set policy route-map RMAP rule 30 set comm-list comm-list 'BGP01'
set policy route-map RMAP rule 30 set comm-list delete
```
Try to delete rule 30
```
vyos@r15# delete policy route-map RMAP rule 30
[edit]
vyos@r15# commit
[ policy route-map RMAP rule 30 set comm-list ]
You must configure a comm-list
[[policy route-map RMAP]] failed
Commit failed
[edit]
vyos@r15#
```
Works with 2 commits:
```
vyos@r15# delete policy route-map RMAP rule 30 set
[edit]
vyos@r15# commit
[edit]
vyos@r15# delete policy route-map RMAP rule 30
[edit]
vyos@r15# commit
[edit]
vyos@r15#
```