filesystem.py: Make CardDF.get_selectables() respect the flags

All other get_selectables() understand a flag like 'FIDS' to request
only the hexadecimal FIDs and not the file names.  However, the
CardEF.get_selectables() ignored those flags and unconditionally
returned the names.

Change-Id: Icdc37cae3eecd36d167da76c30224b9d48c844fd

pySim/filesystem.py

@@ -541,8 +541,10 @@ def get_selectables(self, flags=[]) -> dict:
         """
         # global selectable names + those of the parent DF
         sels = super().get_selectables(flags)
-        sels.update(
-            {x.name: x for x in self.parent.children.values() if x != self})
+        if flags == [] or 'FIDS' in flags:
+            sels.update({x.fid: x for x in self.parent.children.values() if x.fid and x != self})
+        if flags == [] or 'FNAMES' in flags:
+            sels.update({x.name: x for x in self.parent.children.values() if x.name and x != self})
         return sels