This reverts commit 6a85e60c.

Commit 51767e7c "qemu-char: Add new char backend CirMemCharDriver"
introduced a memory ring buffer character device driver named
"memory".  Commit 3949e594 "qemu-char: Saner naming of memchar stuff &
doc fixes" changed the driver name to "ringbuf", along with a whole
bunch of other names, with the following rationale:

    Naming is a mess.  The code calls the device driver
    CirMemCharDriver, the public API calls it "memory", "memchardev",
    or "memchar", and the special commands are named like
    "memchar-FOO".  "memory" is a particularly unfortunate choice,
    because there's another character device driver called
    MemoryDriver.  Moreover, the device's distinctive property is that
    it's a ring buffer, not that's in memory.

This is what we released in 1.4.0.

Unfortunately, the rename missed a critical instance of "memory": the
actual driver name.  Thus, the new device could be used only by an
entirely undocumented name.  The documented name did not work.
Bummer.

Commit 6a85e60c fixes this by changing the documentation to match the
code.  It also changes some, but not all related occurences of
"ringbuf" to "memory".  Left alone are identifiers in C code, HMP and
QMP commands.  The latter are external interface, so they can't be
changed.

The result is an inconsistent mess.  Moreover, "memory" is a rotten
name.  The device's distinctive property is that it's a ring buffer,
not that's in memory.  User's don't care whether it's in RAM, flash,
or carved into chocolate tablets by Oompa Loompas.

Revert the commit.  Next commit will fix just the bug.

Cc: qemu-stable@nongnu.org
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 1374849874-25531-2-git-send-email-armbru@redhat.com
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>