cli: log repositories found on startup

Uses the same log message as before except that instead of path it's id.

[x] I updated the documentation explaining the new behavior if any.
[x] I updated CHANGELOG.md file adding the new feature or bug fix.
[x] I updated go-mysql-server using make upgrade command if applicable.
[x] I added or updated examples if applicable.
[x] I checked that changes on schema are reflected into the documentation, if applicable.

src-d / gitbase