container.settings: fix "setintag" with certain settings

To reproduce the bug:
1. type ":setintag * sort ctime" into the console
2. ensure that the directory ~ is untagged and ~/dl is tagged with "*"
3. change directory to ~/dl/
4. press ^R

The result is that ~ is sorted by ctime even though it shouldn't be.
this is because it uses the settings of fm.thisdir rather than it own
settings.

This commit fixes this bug