fixes #6550 / BZ 1117952 - fix issues with changing org name which affected running db:seed

Without these changes, the user cannot change the default organization
name and re-run 'rake db:seed'.  The reason being, it would attempt
to create an organization with a label that was already in use and
the seed would fail.

In order to address this, this commit does a couple of things:
1. when creating an org, if a label is automatically generated
   and it is already in use, re-generate the label using a uuid.
2. fix an existing validation which was incorrectly comparing
   name=label, label=name, etc. during org create and update.
True, but that is the behavior today in other scenarios (i.e. if the system cannot assign label based on name, use uuid).   It seems like it could be equally confusing to add another algorithm to assigning the label.  E.g. some times it is name, some times it is name+something, some times it is uuid.