Comment 17 for bug 1333694

All this being said, on trusty this bug is valid and still happens. Likely because there are many samba updates available, and it is incorrectly selecting an old one:
root@trusty:~# apt-cache policy samba-common
samba-common:
  Installed: (none)
  Candidate: 2:4.3.11+dfsg-0ubuntu0.14.04.20
  Version table:
     2:4.3.11+dfsg-0ubuntu0.14.04.20+esm8 0
       -32768 https://esm.ubuntu.com/ubuntu/ trusty-infra-security/main amd64 Packages
     2:4.3.11+dfsg-0ubuntu0.14.04.20 0
        500 http://archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
     2:4.1.6+dfsg-1ubuntu2 0
        500 http://archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

Yet it selected 2:4.1.6+dfsg-1ubuntu2.

Xenial (which has 0.16.2) and later behave like in my previous comment. It stops if the required packages are not installed, and packagekit is also not available, and if packagekit is available, it installs what is needed without failing.

Since trusty has reached the normal EOL, I suggest to use the workaround that is to manually install the required packages before invoking the realm tool.