Remove Ubuntu 14.10 (Utopic Unicorn) from build-deb targets

As of July 23, 2015, it is officially EOL (https://lists.ubuntu.com/archives/ubuntu-announce/2015-July/000198.html) and will receive no further updates.

Signed-off-by: Andrew "Tianon" Page <admwiggin@gmail.com>

contrib/builder/deb/ubuntu-debootstrap-utopic/Dockerfile

@@ -1,14 +0,0 @@
-#
-# THIS FILE IS AUTOGENERATED; SEE "contrib/builder/deb/generate.sh"!
-#
-
-FROM ubuntu-debootstrap:utopic
-
-RUN apt-get update && apt-get install -y bash-completion btrfs-tools build-essential curl ca-certificates debhelper dh-apparmor dh-systemd git libapparmor-dev libdevmapper-dev libsqlite3-dev --no-install-recommends && rm -rf /var/lib/apt/lists/*
-
-ENV GO_VERSION 1.4.2
-RUN curl -fSL "https://storage.googleapis.com/golang/go${GO_VERSION}.linux-amd64.tar.gz" | tar xzC /usr/local
-ENV PATH $PATH:/usr/local/go/bin
-
-ENV AUTO_GOPATH 1
-ENV DOCKER_BUILDTAGS apparmor selinux