Comment 4 for bug 1316293

Scratch my supposed fix.; the service started up fine after the reboot, but failed after any subsequent restarts. I'm currently stuck running it in debug as well. Box was installed as 14.04 x64 from scratch; not a 12.04 upgrade.

$ dpkg-query --show amavisd-new
amavisd-new 1:2.7.1-2ubuntu3

uname is 3.13.0-43-generic

mail logs are similar:
Jan 11 22:24:02 bamboo amavis[5657]: logging initialized, log level 5, syslog: amavis.mail
Jan 11 22:24:02 bamboo amavis[5657]: starting. /usr/sbin/amavisd-new at bamboo.slabnet.com amavisd-new-2.7.1 (20120429), Unicode aware, LANG="en_US.UTF-8"
Jan 11 22:24:02 bamboo amavis[5657]: perl=5.018002, user=, EUID: 128 (128); group=, EGID: 138 138 (138 138)
Jan 11 22:24:02 bamboo amavis[5657]: INFO: no optional modules: Unix::Getrusage
Jan 11 22:24:02 bamboo amavis[5657]: SpamControl: attempting to load scanner SpamAssassin, module Amavis::SpamControl::SpamAssassin
Jan 11 22:24:02 bamboo amavis[5657]: SpamControl: scanner SpamAssassin, module Amavis::SpamControl::SpamAssassin
Jan 11 22:24:02 bamboo amavis[5657]: INFO: SA version: 3.4.0, 3.004000, no optional modules: Encode::Detect IP::Country::Fast auto::NetAddr::IP::full6 auto::NetAddr::IP:
:Util::inet_n2dx auto::NetAddr::IP::Util::inet_n2ad auto::NetAddr::IP::Util::inet_any2n auto::NetAddr::IP::Util::ipv6_aton
Jan 11 22:24:02 bamboo amavis[5657]: SpamControl: init_pre_chroot on SpamAssassin done
Jan 11 22:24:02 bamboo amavis[5657]: bind to /var/lib/amavis/amavisd.sock|unix, 127.0.0.1:10024/tcp

...then nothing, though amavisd-new runs fine in debug in the foreground as per original poster's report.