Better command path handling

[xeno010]

Current situation:

// In Config
'dump_command_path' => '' -> Works
'dump_command_path' => 'path_without_slash' -> Fails **
'dump_command_path' => 'path_with_/' -> Works

** sprintf('%smysqldump ...', $this->getDumpCommandPath());
=> path_without_slashmysqldump

My PR fix that:

'dump_command_path' => '' -> Works
'dump_command_path' => 'path_without_slash' -> Works **
'dump_command_path' => 'path_with_/' -> Works

** sprintf('%smysqldump ...', $this->getDumpCommandPath());
=> path_without_slash/mysqldump

[freekmurze]

Thanks!

[freekmurze]

This code of this PR is included in version 2.10.0.