Fix ported.

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    New Contents:
If a device's last path was deleted while the multipathd daemon was trying to reload the device map, or if a ghost path failed, multipathd did not always switch into the recovery mode. As a result, multipath devices could not recover I/O operations in setups that were supposed to temporarily queue I/O if all paths were down. This update resolves both of these issues; multipath now correctly recovers I/O operations as configured.

Reproduced the two issue. Problem have been fixed in 
device-mapper-multipath-0.4.7-42.el5_6.2

Enviroment:
EMC CX RAID 5 LUN Active/Passive setting.
Using this command to remove disk:
echo 1 > /sys/block/sdj/device/delete

multipath.conf:
================================
defaults {
    user_friendly_names     yes
    log_checker_err once
   verbosity 3
}
blacklist {
    devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
    devnode "^hd[a-z]"
        wwid 360a98000486e584c5334615938372d51
        wwid 200173800233600d0
        wwid 36001438005deb4710000500001700000
        wwid 360a98000486e584c53346159384a4963
}
devices {
    device {
        vendor  "DGC"
        product "RAID 5"
        no_path_retry 1
    }
}

For the first issue,
Before fix, we will got this when all path have been removed.
Mar 23 01:00:06 storageqe-08 multipathd: mpath1: Entering recovery mode: max_retries=10
After fix,
Mar 23 02:35:25 storageqe-08 multipathd: mpath1: Entering recovery mode: max_retries=1 


For second issue:
When all path failed (remove ghost path first), the queue has never been failed. dd command keep in S mode.
After pathed, I have tried 10 times, issue  gone.

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2011-0379.html