Memory leak in lobj example code

In the Programmer's Guide, the sample code for accessing large objects
from libpq has two functions with memory leaks.

The functions pickout() and overwrite() malloc space for buf which is
never freed.

See
http://www.postgresql.org/users-lounge/docs/7.0/programmer/largeobjects3207.htm

This problem is also in the 6.5 docs at
http://www.postgresql.org/users-lounge/docs/6.5/programmer/x3184.htm

Nishad
--
"Underneath the concrete, the dream is still alive" -- Talking Heads