Database locking during kprops, MIT 1.8

[Greg Hudson]

On Wed, 2011-06-22 at 18:01 -0400, John Devitofranceschi wrote:
> I was wondering if there was any more clarity to be had around 'issue
> 3' here.

Issue 3 is about the install guide's proviso that:

   * The "call out to `kprop'" mechanism is a bit fragile; if the
     `kprop' propagation fails to connect for some reason, the process
     on the slave may hang waiting for it, and will need to be
     restarted.

After investigation, I believe this proviso is outdated.  In December
2008, Ken committed some changes from Shawn Emery to add a timer to the
loop which waits for a kprop connection.  So the slave should eventually
return to the iprop main loop if the master fails to connect for a full
dump.  (The slave will then probably try to initiate a new full dump.)

Those changes should have landed in 1.7.  I will update our install
guide to remove the proviso.