root@cloud:~# apt-get install nova-novncproxy
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  nova-novncproxy
0 upgraded, 1 newly installed, 0 to remove and 2 not upgraded.
53 not fully installed or removed.
Need to get 0 B/5,660 B of archives.
After this operation, 1,933 kB of additional disk space will be used.
(Reading database ... 68083 files and directories currently installed.)
Unpacking nova-novncproxy (from .../nova-novncproxy_1%3a2013.1.1-0ubuntu2~cloud0_all.deb) ...
dpkg: error processing /var/cache/apt/archives/nova-novncproxy_1%3a2013.1.1-0ubuntu2~cloud0_all.deb (--unpack):
 trying to overwrite '/usr/bin/nova-novncproxy', which is also in package novnc 1:0.4+dfsg+1-7
Processing triggers for ureadahead ...
ureadahead will be reprofiled on next reboot
Errors were encountered while processing:
 /var/cache/apt/archives/nova-novncproxy_1%3a2013.1.1-0ubuntu2~cloud0_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)