No error message when called with non-existent feature

[fbalak]

gdeploy called with configuration file that contains non-existent feature (in reproducer it is aaa) returns no error message and exit code 0. There should be some error message when called invalid file and exit code should be > 0.

Reproducer:

$ echo "[hosts]
> localhost
> 
> [aaa]
> " > test.conf
$
$ gdeploy -c test.conf
$ echo $?
0

Tested with gdeploy 2.0.1 on CentOS Linux 7

[sac]

@fbalak this behavior is because we have some ad-hoc sections present from very early releases. Documented at: https://github.com/gluster/gdeploy/blob/master/gdeploylib/call_features.py#L52

This is a valid issue though. Once we rework and remove those sections, I will fix this.