Bug 15010: Import patron tool creates 'duplicate' restrictions ( debarments )

Bug 15010: Import patron tool creates 'duplicate' restrictions ( debarments )

If a patron has restrictions and a CSV file of patrons to be overwritten
is uploaded but has no debarred / debarredcomment columns, the a new
restriction will be added that combines all the existing restrictions (
i.e. a new debarment based on the existing borrowers.debarred
and borrowers.debarredcomment fields ).

Test Plan:
1) Create a patron with one or more restrictions
2) Import a CSV file that updates that patron, but with no debarred columns
3) Note a new restrictions is created
4) Delete the new restriction
5) Apply this patch
6) Re-import the CSV file again
7) Note that no new restriction is created
8) Add debarred and debarredcomment columns to the CSV file with a test
   date and description
9) Re-import the CSV file again
10) Note the new restriction is added to the patron

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Daniel Grobani <dgrobani@samuelmerritt.edu>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>