chg: [cron] remove ``logrotate`` concerns.

These bits of code were reminiscent of a time where ``logrotate``
charm would be subordinate of ``cron`` charm.

cron/build/Dockerfile

@@ -5,14 +5,7 @@ RUN apt-get update && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
-## XXXvlab: these should be added by logrotate only
-RUN apt-get update && \
-    DEBIAN_FRONTEND=noninteractive apt-get install -y --force-yes netcat-openbsd logrotate && \
-    apt-get clean && \
-    rm -rf /var/lib/apt/lists/*
-
 COPY ./src/usr/bin/lock /usr/bin/lock
-COPY ./src/usr/bin/docker-send-signal /usr/bin/docker-send-signal
 COPY ./src/usr/bin/docker-17.06.2-ce /usr/bin/docker
 
 COPY ./entrypoint.sh /entrypoint.sh

cron/build/src/usr/bin/docker-send-signal

@@ -1,38 +0,0 @@
-#!/bin/bash
-
-exname=$(basename "$0")
-usage="$exname [-h|--help] CONTAINER SIGNAL"
-
-container=
-signal=
-while [ "$1" ]; do
-    case "$1" in
-        "--help"|"-h")
-            echo "$usage" >&2
-            exit 0
-        ;;
-        *)
-            [ -z "$container" ] && { container=$1 ; shift ; continue ; }
-            [ -z "$signal" ] && { signal=$1 ; shift ; continue ; }
-            echo "Unexpected argument '$1'." >&2
-            exit 1
-        ;;
-    esac
-    shift
-done
-
-if [ -z "$container" ]; then
-    echo "You must provide a container name/id as first argument." >&2
-    echo "$usage" >&2
-    exit 1
-fi
-
-if [ -z "$signal" ]; then
-    echo "You must provide a signal to send to $container aargument." >&2
-    echo "$usage" >&2
-    exit 1
-fi
-
-container_id="$(docker inspect --format="{{ .Id }}" "$container")"
-
-echo -e "POST /containers/$container_id/kill?signal=$signal HTTP/1.0\r\n" | nc -U /var/run/docker.sock