Removing preupgrade instructions from Releases/Rawhide

[James Laska]

Greetings,

A tester on #fedora-qa (JustinClift) pointed out that the wiki
instructions for installing Rawhide recommend using 'preupgrade'.  I
know the instructions have been there for some time, but it just
occurred to me that install images are no longer provided for Rawhide.

I have like to removed this section from the wiki [1], and plan to
request an update to releases.txt [2] to no longer offer 'Rawhide'
preupgrades.

Any comments/concerns?

Thanks,
James

[1]
https://fedoraproject.org/wiki/Releases/Rawhide#From_any_release_via_Preupgr...
[2] http://mirrors.fedoraproject.org/releases.txt