XWIKI-10431: In major installations, Filesystem Attachment Store...

XWIKI-10431: In major installations, Filesystem Attachment Store deleteEmptyDirs() can block startup for significant time.
Accidently set the since to 6.0M1, thanks Vincent for catching me on that.

xwiki-platform-tools/xwiki-platform-tool-configuration-resources/src/main/resources/xwiki.properties.vm

@@ -632,7 +632,7 @@ rendering.transformations = $xwikiRenderingTransformations
 # Store
 #-------------------------------------------------------------------------------------
 
-#-# [Since 6.1M1]
+#-# [Since 6.1M2]
 #-# If active, the Filesystem Attachment Store will automatically clear empty directories on startup,
 #-# in some cases this may create undue load on the server and may need to be disabled. To do that,
 #-# set the following to false.