Bug#805444: multipath-tools: Installation fails with "Unit blk-availability.service failed to load"

[Michel Meyers]

Package: multipath-tools
Version: 0.5.0+git1.656f8865-1
Severity: important

Dear Maintainer,

dpkg fails while upgrading multipath-tools. The errors look like this:

Installing new version of config file /etc/init.d/multipath-tools ...
Failed to start multipath-tools.service: Unit blk-availability.service
failed to load: No such file or directory.
invoke-rc.d: initscript multipath-tools, action "start" failed.
dpkg: error processing package multipath-tools (--configure):
 subprocess installed post-installation script returned error exit status 6

I've tried to look for a package containing the blk-availability.service
file but couldn't find one in any Debian release branch.

-- Package-specific info:
Contents of /etc/multipath.conf:
defaults {
        polling_interval        5
        path_selector                "round-robin 0"
        path_grouping_policy    multibus
        path_checker            directio
        rr_min_io               10
        rr_min_io_rq            10
        rr_weight               priorities
        failback                immediate
        no_path_retry           queue
        user_friendly_names      yes
}
blacklist {
        devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
        devnode "^hd[a-z][[0-9]*]"
        devnode "^vd[a-z]"
        devnode "^cciss!c[0-9]d[0-9]*[p[0-9]*]"
        device {
                vendor DEC.*
                product MSA[15]00
        }
}
multipaths {
        multipath {
                wwid 36001405f4600cb3d523ad356adb297de
                alias rsphotoserver_lun1
                path_selector "round-robin 0"
        }
        multipath {
                wwid 36001405ddcb754cd055dd38b8d80a6d2
                alias server1root_vgstorage
                path_selector "round-robin 0"
        }
        multipath {
                wwid 360014051385e8a4d155cd3f54dac97da
                alias vboxserver2
                path_selector "round-robin 0"
        }
}


-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.16.0-4-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages multipath-tools depends on:
ii  init-system-helpers  1.24
ii  initscripts          2.88dsf-59.2
ii  kpartx               0.5.0+git1.656f8865-1
ii  libaio1              0.3.110-2
ii  libc6                2.19-22
ii  libdevmapper1.02.1   2:1.02.110-1
ii  libgcc1              1:5.2.1-23
ii  libreadline6         6.3-8+b3
ii  libsystemd0          227-2
ii  libudev1             227-2
ii  lsb-base             9.20150917
ii  sg3-utils-udev       1.41-1
ii  udev                 227-2

multipath-tools recommends no packages.

Versions of packages multipath-tools suggests:
pn  multipath-tools-boot  <none>

-- no debconf information