[enh] UPNP: various fixes and improvements

[kay0u]

The problem

• typo upnpc -> self.upnpc
• sudo yunohost firewall upnp --debug was crashing with:

26   DEBUG   acquiring lock...
32   DEBUG   lock has been acquired
52   DEBUG   loading python module yunohost.firewall took 0.020s
52   DEBUG   processing action 'yunohost.firewall.upnp'
59   DEBUG   discovering UPnP devices...
3063 DEBUG   found 1 UPnP device(s)
3069 DEBUG   unable to add port 22 using UPnP
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/yunohost/firewall.py", line 245, in open_port
    self.upnpc.addportmapping(
Exception: UnknownError
3146 DEBUG   action executed in 3.094s
3146 DEBUG   lock has been released
3146 ERROR   Could not open port via UPnP

• Ports remained open when upnp was disabled

Solution

• fix typo
• The UnknownError exception occurs when the protocol is not recognized. Use "TCP" instead of "tcp" (same for "UDP") fix the problem.
• Close all ports if they have been opened by us

PR Status

Tested on my server

How to test

...

[alexAubin]

LGTM

Any opinion on this @Salamandar

[kay0u]

PR #2063 on this branch before merging