Was using the '-ne' integer comparison operator to compare UUID
values. This caused error messages like:
/opt/stack/new/devstack/lib/tempest: line 226: [[: dfae26ac-1780-4677-902d: value too great for base (error token is "902d")
Change it to use '!=' string comparison operator
Change-Id: Ib7c9197dd0fe58addf33b4f82beea6de64f6b10b