Cannot delete vuln from DB via MSF RPC

[DanMcInerney]

I suspect this is related to #11755

Steps to reproduce

• Connect to RPC server with pymetasploit3 library

>>> client = MsfRpcClient('password') 

• Write vuln

client.call('db.report_vuln', [{'workspace':'default', 'host':'1.1.1.1', 'name':'test'}])
{'result': 'success'}

• Confirm vuln is written

>>> client.call('db.vulns', [{'workspace':'default'}])
{'vulns': [{'port': None, 'proto': None, 'time': 1555626811, 'host': '1.1.1.1', 'name': 'test', 'refs': ''}]}

• Attempt to delete vuln

>>> client.call('db.del_vuln', [{'workspace':'default', 'host':'1.1.1.1', name='test'}])
{'result': 'success', 'deleted': []}

• Confirm vuln still exists

>>> client.call('db.vuln', [{'workspace':'default', 'host':'1.1.1.1'}])
{'vulns': [{'port': None, 'proto': None, 'time': 1555626811, 'host': '1.1.1.1', 'name': 'test', 'refs': ''}]}

Relevant code:
https://github.com/rapid7/metasploit-framework/blob/master/lib/msf/core/rpc/v10/rpc_db.rb#L1116

Expected behavior

The vuln should be removed from the DB

Current behavior

The vuln is not removed from the DB

System stuff

Metasploit version

Framework: 5.0.16-dev
Console : 5.0.16-dev

I installed Metasploit with:

• Kali package via apt

OS

Kali