gvfs-test: Avoid deadlocks when waiting for CLI user prompts
gvfs-test: Avoid deadlocks when waiting for CLI user prompts

Force subprocess' stdout to be non-blocking, so that we do not potentially wait
forever, but time out properly.

halfline/gvfs,gicmo/gvfs,halfline/gvfs,gicmo/gvfs,gicmo/gvfs,xkahn/gvfs-cmis,xkahn/gvfs-cmis,gicmo/gvfs,xkahn/gvfs-cmis,xkahn/gvfs-cmis,halfline/gvfs