Feedback to user when he tries to rename a kb with an already existing KB name.
Feedback to user when he tries to rename a kb with an already existing
KB name.

inveniosoftware/invenio-formatter,tiborsimko/invenio-formatter,inveniosoftware/invenio-formatter,inveniosoftware/invenio-formatter,tiborsimko/invenio-formatter,tiborsimko/invenio-formatter