NodeSet CLI: use ''' for separator interpretation

This allows the user to give a litteral new line in -S, so both
-S "\n" and -S $'\n' will work

Change-Id: If6671ae36936ef5cf224725b0da1a8316f91825e

Author: martinetd

lib/ClusterShell/CLI/Nodeset.py

@@ -261,7 +261,8 @@ def nodeset():
         return command_list(options, xset, group_resolver)
 
     # Interprete special characters (may raise SyntaxError)
-    separator = eval('\'%s\'' % options.separator, {"__builtins__":None}, {})
+    separator = eval('\'\'\'%s\'\'\'' % options.separator,
+                     {"__builtins__":None}, {})
 
     if options.slice_rangeset:
         _xset = class_set()

tests/CLINodesetTest.py

@@ -200,6 +200,7 @@ def test_008_expand_separator(self):
         self._nodeset_t(["--expand", "-S", ",", "foo[1-2],bar"], None, b"bar,foo1,foo2\n")
         self._nodeset_t(["--expand", "-S", "uuu", "foo[1-2],bar"], None, b"baruuufoo1uuufoo2\n")
         self._nodeset_t(["--expand", "-S", "\\n", "foo[1-2]"], None, b"foo1\nfoo2\n")
+        self._nodeset_t(["--expand", "-S", "\n", "foo[1-2]"], None, b"foo1\nfoo2\n")
 
     def test_009_fold_xor(self):
         """test nodeset --fold --xor"""