prevent an error when passing a frozen string to REXML::Text.new

dup the string passed in instead of cloning so that it's frozen state is ignored

Signed-off-by: URABE, Shyouhei <shyouhei@ruby-lang.org>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31744 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rexml/text.rb

@@ -105,7 +105,7 @@ module REXML
       @normalized = @unnormalized = nil
 
       if arg.kind_of? String
-        @string = arg.clone
+        @string = arg.dup
         @string.squeeze!(" \n\t") unless respect_whitespace
       elsif arg.kind_of? Text
         @string = arg.to_s

test/rexml/test_core.rb

@@ -349,6 +349,9 @@ class Tester < Test::Unit::TestCase
     assert_equal(string, text.to_s)
     text2 = Text.new(text)
     assert_equal(text, text2)
+    string = "Frozen".freeze
+    text3 = Text.new(string)
+    assert_equal(string, text3.to_s)
     #testing substitution
     string = "0 < ( 1 & 1 )"
     correct = "0 &lt; ( 1 &amp; 1 )"