dokku-pg-plugin does not use DOKKU_NOT_IMPLEMENTED_EXIT, leads to misbehaviour with unknown commands

[fwolfst]

(From dokku/dokku#1156)

In a bare install, if I run a valid command, it displays output and exits with 0 (normally).
(assume dokku-remote is an alias for ssh dokku@....)

➜ ~ dokku-remote apps; echo $?
=====> My Apps
ruby-sample
0

If I give an invalid command dokku helps me with message and exit code.

➜ ~ dokku-remote appsitypo; echo $?
! appsi is not a dokku command.
! See dokku help for a list of available commands.
1

Now if I install a dokku-pg-plugin

cd /var/lib/dokku/plugins
git clone https://github.com/Kloadut/dokku-pg-plugin postgresql
dokku plugins-install

the situation changes for worse:

➜ ~ dokku-remote apps; echo $?
=====> My Apps
ruby-sample
0
➜ ~ dokku-remote appsitypo; echo $?
0

I have not needed that yet, but it might be pretty annoying for scripting-stuff-situations.