@jasonnix The Linux distribution operating system restricts certain commands, operations and/or path (location) to the root account, as well as the location owner.
The path your trying to write to is just one such location as the location is read only to non-root users. If you really wish to write to /usr/local/src then root account is required.
If you use the root account to install then the directory and the Xen Orchestra files will be owner by root. You would need to create a non-root user for the xen orchestra server process. As well as change ownership of the Xen Orchestra files and folders to that non-root account. Though at least the ones which Xen Orchestra should be able to modify as required, when needed.
As well as provide the necessary sudo permissions for the necessary commands to that account.
Using root account to run exposes any vulnerabilities present to the capacity of being exploited as root (aka Administrator) privileges.
Also how good is your internet connection and your connection to GitHub? Cause you could be experiencing a time out packet loss connection issue.