Log Message:
Update dovecot2-pigeonhole to 0.4.8.

v0.4.8 15-05-2015 Stephan Bosch <stephan@rename-it.nl>

	* LDA Sieve plugin: Dovecot changed the deliver_log_format setting to include
	  %{delivery_time}. This prompted changes in Pigeonhole that make this release
	  dependent on Dovecot v2.2.17.
	+ Implemented magic to make sieve_default script visible from ManageSieve
	  under a configurable name. This way, users can see the default rules, edit
	  them and store a private adjusted version. This could also be achieved by
	  copying the default script into the user's script storage, but updates to
	  the global sieve_default script would be ignored that way.
	+ ManageSieve: Implemented support for reporting command statistics at
	  disconnect. Statistics include the number of bytes and scripts uploaded/
	  downloaded/checked and the number of scripts deleted/renamed.
	- Fixed problem in address test: erroneously decoded mime-encoded words in
	  address headers.
	- extprograms plugin: Fixed failure occurring when connecting to script
	  service without the need to read back the output from the external program.
	- Fixed bug in script storage path normalization occurring with relative
	  symbolic links below root.
	- Fixed and updated various parts of the documentation
	- ManageSieve: Used "managesieve" rather than "sieve" as \ 
login service name,
	  which means that all managesieve-specific settings where ignored.
	- Managesieve: Storage quota was not always enforced properly for scripts
	  uploaded as quoted string. Nobody uses that, but it is allowed in the
	  specification and we support it, so it should work properly.