Bug 30511: Don't lock up entire database while running koha-dump

Test plan:
1. Apply the patch
2. Restart services
3. Run koha-dump
4. Confirm the .sql.gz and .tar.gz files are generated successfully

Sponsored-by: Catalyst IT

Signed-off-by: David Cook <dcook@prosentient.com.au>

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>

debian/scripts/koha-dump

@@ -79,13 +79,13 @@ dump_instance()
     then
         schemadump="$backupdir/$name-schema-$date.sql"
         [ "$quiet" = "no" ] && echo "* schema to $schemadump"
-        mysqldump $dbflag -d --host="$mysqlhost" \
+        mysqldump $dbflag -d --host="$mysqlhost" --single-transaction \
             --user="$mysqluser" --password="$mysqlpass" "$mysqldb" | sed --expression='s/ AUTO_INCREMENT=[0-9]\+//' > "$schemadump"
         chown "root:$name-koha" "$schemadump"
         chmod g+r "$schemadump"
     else
         [ "$quiet" = "no" ] && echo "* DB to $dbdump"
-        mysqldump $dbflag --host="$mysqlhost" \
+        mysqldump $dbflag --host="$mysqlhost" --single-transaction \
             --user="$mysqluser" --password="$mysqlpass" "$mysqldb" |
             gzip > "$dbdump"
         chown "root:$name-koha" "$dbdump"