* test/ruby/test_array.rb (test_rotate!): fix expected message.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@29588 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_array.rb

@@ -2155,7 +2155,7 @@ class TestArray < Test::Unit::TestCase
     assert_equal([], a.rotate!(-13))
     a = [].freeze
     e = assert_raise(RuntimeError) {a.rotate!}
-    assert_match(/can't modify frozen array/, e.message)
+    assert_match(/can't modify frozen/, e.message)
     a = [1,2,3]
     assert_raise(ArgumentError) { a.rotate!(1, 1) }
   end