Remove compatibility code for multiple versions of BTL_IN_OPAL,
BTL_VERSION, and RCACHE_VERSION. This stuff was really only necessary
when we were actively swapping code between multiple release branches
that had large variations in core OMPI infrastructure. These large
variations have now been around for quite a while, so the need for
this "compat" layer is significantly reduced. It hasn't been removed
simply because a few of the "compat" names a slightly more friendly
than the real names (e.g., the SEND/RECV/PUT names).
Signed-off-by: Jeff Squyres <jsquyres@cisco.com>