varlink Commit API returns a lot of garbage output which makes it really slow

[KKoukiou]

/kind bug

Description
Commit API prints out a lot of garbage.

Steps to reproduce the issue:

1. sudo varlink call unix:/run/podman/io.podman/io.podman.Commit '{"name": "8ff65ed72f78", "image_name": "test_image"}' --more

Describe the results you received:

There are A LOT of empty reply messages in the reply when using more which make the processing of the Commit API result unnecessary slow.

$ sudo varlink call unix:/run/podman/io.podman/io.podman.Commit '{"name": "8ff65ed72f78", "image_name": "test_image"}' --more | grep 'logs": \[\]' | wc -l
153650

Describe the results you expected:
All empty replies (153650 lines!!!) should be discarded since they are of no usefulness

Output of podman version:

$ podman --version
podman version 1.4.2