ownCloud/client/install error

This is what happens when I type apt-get -f install after an unsuccessful attempt to install libowncloudsync0:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Correcting dependencies... Done
The following extra packages will be installed:
  libowncloudsync0
The following NEW packages will be installed:
  libowncloudsync0
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
Need to get 0 B/374 kB of archives.
After this operation, 1,242 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
(Reading database ... 376046 files and directories currently installed.)
Preparing to unpack .../libowncloudsync0_2.1.1-1.1_amd64.deb ...
Unpacking libowncloudsync0:amd64 (2.1.1-1.1) ...
dpkg: error processing archive /var/cache/apt/archives/libowncloudsync0_2.1.1-1.1_amd64.deb (--unpack):
 trying to overwrite shared '/etc/ownCloud/sync-exclude.lst', which is different from other instances of package libowncloudsync0:amd64
Errors were encountered while processing:
 /var/cache/apt/archives/libowncloudsync0_2.1.1-1.1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Tentatively: it's trying to install two copies of libowncloudsync0. Note that it's listed both "extra packages" and "NEW packages".