macosx: fixed indention of the sidebar icons (refs #5742)

(cherry picked from commit 65d1a6dc)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/macosx/PXSourceList.m

@@ -336,7 +336,7 @@ NSString * const PXSLDeleteKeyPressedOnRowsNotification = @"PXSourceListDeleteKe
 	}
 	else
 	{
-		CGFloat leftIndent = [self levelForRow:row]*[self indentationPerLevel]+DISCLOSURE_TRIANGLE_SPACE;
+		CGFloat leftIndent = ([self levelForRow:row] -1)*[self indentationPerLevel]+DISCLOSURE_TRIANGLE_SPACE;
 
 		//Calculate space left for a badge if need be
 		CGFloat rightIndent = [self sizeOfBadgeAtRow:row].width+ROW_RIGHT_MARGIN;