predict-built programs require a specific PATH to run

[maya-rv]

I doubt this will affect most users.
I made an install to PREFIX=$HOME, and so rvpa is $HOME/bin/rvpa.
This means that having a root-running daemon will probably not have it in PATH, and I get:

knotd: RV-Predict/C could not start an analysis process: No such file or directory
knotd: RV-Predict/C event serialization failed: Broken pipe
Aborted

Also, this error message isn't good enough to be fixed by a user.

[maya-rv]

we use get_binary_path to find rvpa, except the built program and rvpa aren't necessarily installed to the same location.