module-zeroconf-discover loads module-pulse-tunnel for each entity
exposed on the network. Previously, however, the destroy event
of the loaded pulse-tunnel modules were not handled.
This resulted in a use-after-free because both `pw_context_destroy()`
and `module-zeroconf-discover.c:impl_free()` tried to destroy
the pulse-tunnel modules. The reason for that is that since
1de16afc40 the modules
are prepended to the module list of the context, not appended,
therefore modules are destroyed in LIFO order, thus the pulse-tunnel
modules were destroyed before the zeroconf-discover module that
loaded them.
Fix that by handling the destroy event of the loaded pulse-tunnel
modules.
Fixes#1653
This allows to get rid of the empty if block in comparison to
channel_map, and makes it clear that the comparison is useless. So in
the next commit we will remove it.
Fixes an LGTM warning:
Empty block without comment
Just like the real free() we should just ignore a NULL pointer, makes the
caller code easier for those instances where properties are optional.
Patch generated with concinelle with a few manual fixes.
