migrate:reset: --path may be a single string

Fixed situation when `migrate:reset` is run from application:
```
Artisan::call('migrate:reset', [
    '--path' => 'database/migrations',
]);
```

src/Illuminate/Database/Console/Migrations/BaseCommand.php

@@ -18,7 +18,7 @@ protected function getMigrationPaths()
         // migrations may be run for any customized path from within the application.
         if ($this->input->hasOption('path') && $this->option('path')) {
             $paths = [];
-            foreach ($this->option('path') as $path) {
+            foreach ((array) $this->option('path') as $path) {
                 $paths[] = $this->laravel->basePath().'/'.$path;
             }