Bookmark: Fix empty name when path has trailing slash

Normalize the path / remove redundant separator before trying to get the
folder name.

Reported-by: Vdragon
Signed-off-by: Minarto Margoliono lie.r.min.g@gmail.com
Merge pull request #295 from mmargoliono/288

Bookmark: Fix empty name when path has trailing slash

Signed-off-by: David Aguilar <davvid@gmail.com>