Need to close every endpoint we open, or the MX progress thread doesn't die,

which can cause segfaults on shutdown.  Calling mx_finalize() isn't enough
to shutdown the thread, so must close endpoints as well.

Refs trac:513

This commit was SVN r12908.

The following Trac tickets were found above:
  Ticket 513 --> https://svn.open-mpi.org/trac/ompi/ticket/513

ompi/mca/btl/mx/btl_mx.c

@@ -419,6 +419,8 @@ int mca_btl_mx_send( struct mca_btl_base_module_t* btl,
 int mca_btl_mx_finalize( struct mca_btl_base_module_t* btl )
 {
     mca_btl_mx_module_t* mx_btl = (mca_btl_mx_module_t*) btl; 
+
+    mx_close_endpoint(mx_btl->mx_endpoint);
     
     OBJ_DESTRUCT( &mx_btl->mx_lock );
     OBJ_DESTRUCT( &mx_btl->mx_peers );