syntax error fix

vagrant provision fails using centos63 box with ruby 1.8.7

<pre>
[2013-01-11T15:56:01+01:00] FATAL: Stacktrace dumped to /tmp/vagrant-chef-1/chef-stacktrace.out
[2013-01-11T15:56:01+01:00] FATAL: SyntaxError: compile error
/tmp/vagrant-chef-1/chef-solo-1/cookbooks/memcached/recipes/default.rb:21: syntax error, unexpected tCONSTANT, expecting kTHEN or ':' or '\n' or ';'
...latform_family'] == "rhel" AND node['platform_version'].to_i...
                              ^
/tmp/vagrant-chef-1/chef-solo-1/cookbooks/memcached/recipes/default.rb:23: syntax error, unexpected kEND, expecting $end
</pre>