[8.1] Deprecated function: explode(): Passing null to parameter #2 ($string)

[argiepiano]

This is thrown when backing up the entire site and db.

Deprecated function: explode(): Passing null to parameter #2 ($string) of type string is deprecated in backup_file->set_file_info() (line 521 of /Users/XXX/Sites/localhost/bdtesting/modules/backup_migrate/includes/files.inc).

The problem is that backup_file::set_file_info() expects a file name as part of the received array. But backup_migrate_files_destination_archivesource::get_db() doesn't pass a filename, since the file has already been initialized previously when backing up the site files. The solution is to avoid doing the explode if the array is empty.

[argiepiano]

PR #132