CacheFs and related components need to be called out as obsoleted in the release
notes.

Do we need to actually obsolete the components?

From the 5.2 Release Notes:
http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.2/html/Release_Notes/singles/relnotesU2-x86.html

"""
Thanks to the help of upstream developers and testing customers, the
FS-Cache feature has undergone significant changes in line with upstream
FS-Cache implementation. Consequently, the technology preview
implementation of FS-Cache in this release is now rendered obsolete. 

As such, Red Hat does not recommend the usage of FS-Cache. Note that
FS-Cache will also be likely disabled for the next minor releases. 

Red Hat will be focusing on further refining this feature as per
upstream specifications. Once an acceptable level of invasiveness and
compatibility is reached, FS-Cache will then be re-introduced in Red Hat
Enterprise Linux. 
"""