Feature request: more helpful error message if there is no remote "origin"

[mwachs5]

If you run "wit update" in a workspace where (due to development on a package) you have no remote called "origin", you get a fatal error:

wit.gitrepo.GitError: Command [git remote get-url origin] in [...] exited with non-zero exit status [128]
stdout: []
stderr: [fatal: No such remote 'origin']

If you have something called "origin" and somethign called say "private" and your workspace wants to be using the remote you are calling "private" as "origin", the error message is helpful and basically tells you to rename "private" to "origin". Would request a similar helpful error message. And, apparently wit update requires the packages' remotes to be "origin" is probably worth documenting.

[mwachs5]

please note that this may only apply if you have already done stuff in your wit workspace, this was in a workspace that had already been --init , and then i want to chagne the remote of a package.