Wrap each cleanup step in a separate try/catch in exit func.

Clean up as much as possible.

exec/imapservice.js

@@ -1549,16 +1549,21 @@ function old_unlock_cfg()
 
 function exit_func()
 {
+	try {
 		close_sub();
+	}
+	catch(error) {}
 	if (locked_code !== undefined) {
+		try {
 			log("At exit, "+locked_code+" is still locked.");
 			unlock_cfg(locked_code);
 		}
+		catch(error) {}
+	}
 	try {
 		save_cfg();
 	}
-	catch (error) {
-	}
+	catch (error) {}
 }
 
 function binify(seen)