Workaround a frozen string issue in testing

Author: DavidS

lib/puppet/parser/functions/pw_hash.rb

@@ -60,7 +60,8 @@
   salt = "$#{hash_type}$#{args[2]}"
 
   # handle weak implementations of String#crypt
-  if 'test'.crypt('$1$1') != '$1$1$Bp8CU9Oujr9SSEw53WV6G.'
+  # dup the string to get rid of frozen status for testing
+  if ('test'.dup).crypt('$1$1') != '$1$1$Bp8CU9Oujr9SSEw53WV6G.'
     # JRuby < 1.7.17
     # MS Windows and other systems that don't support enhanced salts
     raise Puppet::ParseError, 'system does not support enhanced salts' unless RUBY_PLATFORM == 'java'