Do not sort keys when reading

For purpose of rewriting user's INI, we don't want to mess it up more
than is necessary.

src/include/ini.sh

     # List keys from a section
     #
     local sct=$1    # section of interest
-    _ini_grepsec "$sct" | cut -d= -f1 | sort | uniq
+    _ini_grepsec "$sct" | cut -d= -f1 | awk '!x[$0]++'
 }
 
 _ini_maybe_expand() {