add a new --force flag for backups that allows disable and delete to skip error checking

Closes: #458250

platform/backup.provision.inc

@@ -51,7 +51,7 @@ function drush_provision_drupal_provision_backup($url) {
   drush_log(dt("Adding sites directory to !backup_file", array('!backup_file' => $backup_file)), 'backup');
   $result = provision_shell_exec("cd %s; tar -rf %s * ", drush_get_option('sites_path') . "/$url",  $backup_file);
 
-  if (!$result) {
+  if (!$result && !drush_get_option('force', false)) {
     drush_set_error('PROVISION_BACKUP_FAILED', dt("Could not back up sites directory for drupal"));
   }
 }

platform/delete.provision.inc

@@ -10,7 +10,9 @@ function drush_provision_drupal_provision_delete_validate($url = NULL, $backup_f
  * Before starting to delete the site, make a backup
  */
 function drush_provision_drupal_pre_provision_delete($url, $backup_file = NULL) {
-  drush_invoke('provision backup', $url, $backup_file);
+  drush_set_option('force', true, 'process');
+  drush_invoke("provision backup", $url, $backup_file);
+  drush_unset_option('force', 'process');
 }
 
 /**

platform/disable.provision.inc

@@ -23,7 +23,9 @@ function drush_provision_drupal_provision_disable_validate() {
  * Make a backup of the site before we mess with it
  */
 function drush_provision_drupal_pre_provision_disable($url, $backup_file = null) {
+  drush_get_option('force', true, 'process');
   drush_invoke("provision backup", $url, $backup_file);
+  drush_unset_option('force', 'process');
 }
 
 /**