Unload perl modules when they are unloaded.

This should make /znc reloadmod and /znc updatemod to work as expected.
So developers don't need to restart znc each time when debugging perl modules anymore.

git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@2184 726aef4b-f618-498e-8847-2d620e286838

modules/modperl/modperl.i

@@ -189,6 +189,12 @@ typedef vector<pair<CString, CString> > VPair;
 	}
 %}
 
+%inline %{
+	void _CleanupStash(const CString& sModname) {
+		hv_clear(gv_stashpv(sModname.c_str(), 0));
+	}
+%}
+
 %perlcode %{
 	package ZNC;
 	*CONTINUE = *ZNC::CModule::CONTINUE;