Generating repositories from a template is done inside a transaction.
Manual rollback on error is not needed and it always results in error
"repository does not exist".
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
MIME types can have multiple optional parameters, eg:
video/webm; codecs="w/e codec"; charset="binary"
This commit replaces the usage of regex for getting the "type/subtype"
with mime.ParseMediaType.
