BUG-14945 Disable foreign keys verification when generating a backup.

The statement SET FOREIGN_KEY_CHECKS=0; was added when the sql script is been generated, when backuping a workspace. This was added in case that a table in the database has a foreign key.

When a table has a foreign key some operations are not allowed create/delete/update, because of the restrictions of the foreing key. So, to allow this operations we disabled the foreign key checks (SET FOREIGN_KEY_CHECKS=0;) until we have all the tables created in the database.

gulliver/system/class.dbMaintenance.php

@@ -500,6 +500,7 @@ class DataBaseMaintenance
         $schema .= " -- Tables:    " . (count( $aTables )) . "\n";
         $schema .= " -- Date:      " . (date( 'l jS \of F Y h:i:s A' )) . "\n";
         $schema .= " --\n\n";
+        $schema .= "SET FOREIGN_KEY_CHECKS=0; \n\n";
 
         $file = fopen( $outfile, "w+" );