The web page from which this call is taken has a readme selector
and a default value of "Default" that we're not sending in this
request. Send it to avoid gitea not being able to find the empty
readme.
Also, add gitea-git-repos to the files section of system-config-run-gitea
so that we actually test it.
Change-Id: Ieec94aadb63fa097f10a3f325dd105b30e610dd9