calamaris cronjob setup doesn't allow specification of log file directory

[Karl-Philipp Richter]

The `cron` job `/etc/cron.daily/calamaris` invokes `/usr/lib/calamaris/calamaris-cron-script` which parses `/etc/calamaris/cron.conf` which doesn't allow to specify the log file directory to parse (only the name of the log file and a mode which doesn't allow it to cover custom installation prefixes, like `/usr/local/`).

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: calamaris 2.99.4.2-1
Uname: Linux 4.3.3-040303-generic x86_64
NonfreeKernelModules: zfs zunicode zcommon znvpair zavl
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
Date: Sat Jan 16 13:09:24 2016
InstallationDate: Installed on 2015-04-20 (270 days ago)
InstallationMedia: Ubuntu-Server 14.10 "Utopic Unicorn" - Release amd64 (20141022.2)
PackageArchitecture: all
ProcEnviron:
 TERM=screen
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: calamaris
UpgradeStatus: Upgraded to wily on 2015-10-26 (82 days ago)
mtime.conffile..etc.calamaris.calamaris.conf: 2016-01-13T01:54:21.507410