Bug 7360 Import Default framework into other deletes default Framework

Bug 7360 Import Default framework into other deletes default Framework

Step to reproduce :
- export default framework as SQL
- create new framework
- Import the exported SQL file into this new framework.
Go to default framework :
It disappeared.

If some libraries want to share default frameworks, then it is a major bug.
This patch fixes the test in order to cope with 0 character framework name.

Signed-off-by: François Charbonnier <francois.charbonnier@biblibre.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>