Revert r30966.

cmr=v1.8.1:reviewer=ompi-gk1.8
btl_usnic_connectivity.h: fix PACK_BYTES macro

We're passing a char foo[x] into PACK_BYTES, so we don't need to take
its address in the macro.  This is parallel to the UNPACK_BYTES macro
(where we pass a char bar[x] into it, and don't take its address in
the macro).

The value we're packing is only used to output in a show_help message,
which is why this wasn't noticed before (i.e., it's not used in
network or addressing that would have caused a failure).

cmr=v1.8.2:reviewer=dgoodell
Now that the abort code no longer involves a blocking rml send section, apps that call show_help followed by abort are not printing their error message. So block them in show_help until that message gets out.