I hate this commit.

Revert much of the implementation of C++98/03 [temp.friend]p5 in
r103943 and its follow-ons r103948 and r103952. While our
implementation was technically correct, other compilers don't seem to
implement this paragraph (which forces the instantiation of friend
functions defined in a class template when a class template
specialization is instantiated), and doing so broke a bunch of Boost
libraries. 

Since this behavior has changed in C++0x (which instantiates the
friend function definitions when they are used), we're going to skip
the nowhere-implemented C++98/03 semantics and go straight to the
C++0x semantics.

This commit is a band-aid to get Boost up and running again. It
doesn't really fix PR6952 (which this commit un-fixes), but it does
deal with the way Boost.Units abuses this particular paragraph.

llvm-svn: 104014