Small CLI fix on "discover absolute path"

This requires just some small improvements, the error itself being harmless, but annoying.

$ immuadmin-090 login immudb
ERROR 2021/01/28 09:46:25 Couldn't discover absolute path
ERROR 2021/01/28 09:46:25 getwd: no such file or directory
Password:
logged in
$

immuadmin-090 is just a sym link:

$ which immuadmin-090
/home/{user}/apps/bin/immuadmin-090
$
$ ls -l `which immuadmin-090`
lrwxrwxrwx 1 {user} {group} 25 Jan 27 13:37 /home/{user}/apps/bin/immuadmin-090 -> ../immudb/0.9.0/immuadmin
$ 

However, this is happening even if the binary is called directly:

$ ~/apps/immudb/0.9.0/immuadmin status       
ERROR 2021/01/28 09:53:05 Couldn't discover absolute path
ERROR 2021/01/28 09:53:05 getwd: no such file or directory
OK - server is reachable and responding to queries
$