Description of problem:

Since the Kernel has support the ring buffer reset feature, which will fix https://bugzilla.redhat.com/show_bug.cgi?id=1596684#c5 stuck bug.

There has two ways to fix this:
1, set the cmd_time_out to none zero to fire the SCSI cmds in ring buffer
2, reset the ring buffer for fire the stuck SCSI cmds, and this BZ is for this case.

The tcmu-runner patches are:

commit 5bf4f822c5d195a5588908eefffeae36ef9e0080
Author: Mike Christie <mchristi>
Date:   Thu Dec 14 20:01:00 2017 -0600

    libtcmu: fix unclean shutdown and restart
    
    If we restart a daemon using libtcmu while IO is in flight
    the kernel could have commands partially completed. This
    patch has us block the device so new IO is stopped, and
    then we reset the ring to a clean state.


commit 9d5562056953a465e3b21efa7a98048026dcc443
Author: Xiubo Li <xiubli>
Date:   Sat Mar 3 23:08:01 2018 -0500

    libtcmu: add tcmu_is_ring_reset_support support
    
    This will compatible with the old kernel version which could
    not support the ring reset operations.
    
    Signed-off-by: Xiubo Li <xiubli>


commit 12d551bb6eafa71e91ca702a9f5d790aa3a08c57
Author: Mike Christie <mchristi>
Date:   Thu Dec 14 20:04:39 2017 -0600

    runner/lib: flush device during shutdown
    
    If remove_device is called during device removal then the kernel
    will not have done the REMOVE event until all IO has stopped
    and new IO will not be sent.
    
    If remove_device is called due to the daemon/app being stopped
    then the kernel will not have been notified. This has the lib
    block new IO and wait for the commands in the ring to be
    completed normally before removing the device.
    
    If for some reason we hang, then we can still kill runner
    and the previous patch will handle any cleaned up needed.

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