Only set ompi_mpi_leave_pinned (a bool) to true if the MCA param value

is >= 1.  The default value of the MCA param is now -1, which means
"let someone else turn it on if they want to."  So we should default
to ''off'' (false), and let the openib BTL (etc.) turn it on if it
can/wants to.

Failure to do this will default _pipeline to true because
-1(int)==true(bool).  This causes a problem if the user tries to set
mpi_leave_pinned_pipeline to 1: they'll get a warning that you can't
set both _pinned and _pinned_pipeline to 1.  This happens because
_pinned will get the bool-ified value of of the MCA parameter (-1),
and then the user sets the value of _pinned_pipeline to 1/true.
Hence, both of them are set to true.  Bzzt!

This commit was SVN r19942.

ompi/runtime/ompi_mpi_params.c

@@ -240,7 +240,7 @@ int ompi_mpi_register_params(void)
                                 "Whether to use the \"leave pinned\" protocol or not.  Enabling this setting can help bandwidth performance when repeatedly sending and receiving large messages with the same buffers over RDMA-based networks (0 = do not use \"leave pinned\" protocol, 1 = use \"leave pinned\" protocol, -1 = allow network to choose at runtime).",
                                 false, false,
                                 ompi_mpi_leave_pinned, &value);
-    ompi_mpi_leave_pinned = value;
+    ompi_mpi_leave_pinned = (value >= 1) ? true: false;
 
     mca_base_param_reg_int_name("mpi", "leave_pinned_pipeline",
                                 "Whether to use the \"leave pinned pipeline\" protocol or not.",