Log Message:
dovecot2-pigeonhole: updated to 0.5.4

v0.5.4:
* Adjustments to several changes in Dovecot v2.3.4 make this Pigeonhole
  release dependent on that Dovecot release; it will not compile against
  older Dovecot versions. And, conversely, you need to upgrade
  Pigeonhole when upgrading Dovecot to v2.3.4.
* The changes regarding the default postmaster_address in Dovecot v2.3.4
  mainly apply to Pigeonhole. The new default should work for all
  existing installations, thereby fixing several reported v2.3/v0.5
  migration problems.
- IMAP FILTER=SIEVE capability: Fix assert crash occurring when running
  UID FILTER on a Sieve script with errors.