Log Message:
mail/dovecot2-pigeonhole: update to 0.5.7.2

Update dovecot2-pigeonhole to 0.5.7.2.

Changes
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* CVE-2019-11500: ManageSieve protocol parser does not properly handle
NUL byte
  when scanning data in quoted strings, leading to out of bounds heap
  memory writes. Found by Nick Roessler and Rafi Rubin.