Remove trace buffer flush at end of shutdown path

During early boot fails (for example, HBD secure verification fail), the
trace daemon is not yet loaded.  In this case, invoking trace flush on the
shutdown path will hang the shutdown handler and prevent Hostboot from TIing.
This patch removes that final trace flush.

Change-Id: I7ce587e648da42a017ff1304d943d0f2201eced2
CQ: SW451419
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/69175
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Reviewed-by: Nicholas E. Bofferding <bofferdn@us.ibm.com>

src/usr/initservice/baseinitsvc/initservice.C

@@ -989,9 +989,6 @@ void InitService::_doShutdown(uint64_t i_status,
                  i_error_info,
                  true); // Force write
 
-    // Ensure all traces get flushed to the console
-    TRAC_FLUSH_BUFFERS();
-
     shutdown(iv_worst_status,
              i_payload_base,
              i_payload_entry,