Add a comment to make Jeff happier...

Refs trac:4340

This commit was SVN r30980.

The following Trac tickets were found above:
  Ticket 4340 --> https://svn.open-mpi.org/trac/ompi/ticket/4340

orte/test/system/sigusr_trap.c

@@ -14,6 +14,9 @@
 #include "orte/runtime/orte_globals.h"
 #include "orte/runtime/runtime.h"
 
+/* yeah, we know it isn't safe to call fprintf inside signal handlers,
+ * but this is good enough for this test
+ */
 void sigusr_handler(int signum)
 {
     switch (signum) {