Make Bamboo EC2 Wizard to preserve proxy settings during upgrade

Problem Definition

When we use the Bamboo EC2 wizard to install Bamboo and when we run upgradeBamboo.sh to upgrade Bamboo, it fails to copy over the proxy settings we have already set in /media/atlassian-data/installs/bamboo/atlassian-bamboo-x.xx.x/conf/server.xml

Suggested Solution

The Proxy details that we have already set in server.xml should be copied over in the successive version to which Bamboo is upgrading to.