fix(oli): oli commands don't work properly for files in CWD

[sarutak]

Related issue: #2834

Given we have a directory d and a file d/f, and the current working directory is d.
If we run oli stat for f like as follows, it works.

$ oli stat ./f

But if we omit ./, it doesn't work.

$ oli stat f
Error: ConfigInvalid (permanent) at  => root is not specified

The cause is that root directory is not set to fs_builder as the error message says.

[Xuanwo]

Thanks!