Update ruby to patchlevel 353 (security update)

https://www.ruby-lang.org/en/news/2013/11/22/heap-overflow-in-floating-point-parsing-cve-2013-4164/

doc/install/installation.md

@@ -118,8 +118,8 @@ Remove the old Ruby 1.8 if present
 Download Ruby and compile it:
     mkdir /tmp/ruby && cd /tmp/ruby
-    curl --progress ftp://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-p247.tar.gz | tar xz
-    cd ruby-2.0.0-p247
+    curl --progress ftp://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-p353.tar.gz | tar xz
+    cd ruby-2.0.0-p353
     ./configure --disable-install-rdoc
     make
     sudo make install