Bug 6880- Reason for suggestions do not save

Bug 6880- Reason for suggestions do not save

The fix for Bug 1883 seems to have lacked the necessary
update to the database to add the "patronreason" column
to the suggestions table. This patch does so.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Patch adds database update and change to kohastructure.
After this patch is applied, the patron's reason for
making a suggestion (form in opac) is saved to the database
correctly. The reason is also shown in the detail view
of the suggestion.

This needs to be backported to 3.6

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>