Add support for out-of-$HOME Juniper binaries

[ktims]

Needed for 'nosuid' support in $HOME. Modern Ubuntus at least offer encrypted home directories. These are mounted 'nosuid' which means that the automatically installed ncsvc under $HOME can't run as root, which is required.

Add support for an environment variable 'JNPATH' to override default JNPATH. ncsvc still writes logs to the $HOME directory so make the log reader look there too.

Not necessarily an elegant solution but works for me.