Fix path to ignored only root log, img and cache folder

Prestashop.gitignore

@@ -7,9 +7,9 @@ config/settings.*.php
 # The following files are generated by PrestaShop.
 
 admin-dev/autoupgrade/
-cache/
+/cache/*
 config/xml/*.xml
-log/
+/log/*
 *sitemap.xml
 themes/*/cache/
 modules/*/config*.xml
@@ -21,5 +21,5 @@ admin-dev/backups/
 admin-dev/export/
 admin-dev/import/
 download/
-img/
+/img/*
 upload/