fix/recover - fifo control timeout looking for ack

[guruofquality]

Seen on some machines, this is probably a network issue of dropped packets causing the control fifo to lose package and causing the host code to error out. Although the exact cause is not known, a possible work-around involves shrinking the control fifo window size to 0 so multiple control packets will not be in-flight -- needs testing.

[guruofquality]

I have pushed an extra debugging hook onto master: 08c05c5

This commit should have no changes by default, however, one can specify

--args="fifo_ctrl_window=0"

on systems that are exhibiting the problem to test if the errors go away. At least I hope that is the case, and this change provides a way to move forward while debugging this issue.