content: fix the install link for 4.5 on the downloads page
content: fix the install link for 4.5 on the downloads page

Signed-off-by: Rohit Yadav <902b9eb5dd62819678163bd5e00fbf0cbc7c264b@shapeblue.com>

apache/cloudstack-www,terbolous/cloudstack-www,terbolous/cloudstack-www,pdion891/cloudstack-www,resmo/cloudstack-www,apache/cloudstack-www,terbolous/cloudstack-www,apache/cloudstack-www,pdion891/cloudstack-www,terbolous/cloudstack-www,resmo/cloudstack-www,apache/cloudstack-www,resmo/cloudstack-www,pdion891/cloudstack-www,pdion891/cloudstack-www,apache/cloudstack-www