pkg: Can't install pgAdmin3

[Walter Hurry]

I have switched (mostly) to binary packages. However, I cannot install 
databases/pgadmin3 using 'pkg install pgadmin3'.

The reason is that it tries to install postgresql92-client first, which 
fails as I already have postgresql93-client installed.

Why is pkg unable to use the  existing postgresql93-client? pgadmin3 
builds and installs quite happily from the port.

Incidentally, I have the same problem with psycopg2.