Often /usr is a separate mountpoint. On shutdown /usr is unmounted, but /sbin/upsdrvctl is linked on libz.so.1 Search on binaries placed in /bin /sbin for link to the libz.so.1 show at list these packages: cman info kexec-tools nut rpm util-linux Maybe it would be better to place libz.so* at /lib because many binaries from /bin /sbin wanted libz.so? Please consider that.
*** Bug 492882 has been marked as a duplicate of this bug. ***
*** Bug 554963 has been marked as a duplicate of this bug. ***
*** Bug 544317 has been marked as a duplicate of this bug. ***
This issue sounds like a non-critical problem that should be resolved in future versions of RHEL. If you feel that this issue should have higher priority please contact redhat.com/support.