CMFileManager: Fix quickfoldersearch command for files with whitespaces

This change fixed the quickfoldersearch command used by InlineAutocompleteTextView
widget, when retrieve items with some whitespace in its name.
Replace awk by cut command, and redirect stderr output of ls to /dev/null.

Change-Id: Id039e573dc5e6ae5755b3251f014f34cd104f426