[patch] fix pr reference syntax in gdb.c++/method.exp

[Michael Snyder]

Michael Elizabeth Chastain wrote:
> 
> Hmmm.  Sometimes, like this time, I post patches to testsuite/gdb.c++
> that I am committing immediately.  And sometimes, I post patches for
> testsuite/gdb.c++ and give people a day or two to comment before I commit.
> Right now I am marking both of these as "[patch]".

I think the custom is to mark the second type as "[RFA]".

> Michael Snyder writes:
> > If you want to avoid ambiguity, you could say "committed"
> > in your original "PATCH" message.
> 
> I will do that, unless Andrew has something to say (I thought he
> liked to see explicit "committed" messages to help him mananage
> his inbox).

I think that was meant to apply to the "[RFA]" genre.