In the course of doing some testing with how orted's
handle signaled child processes, found out that very
often doing a kill -9 on a process on a node just
results in the job hanging. The problem was that the
orted odls/errmgr was not properly handling the exit_code
being returned from waitpid. Now mark the proc state
as ORTE_PROC_STATE_ABORTED_BY_SIG if the exit_code
from waitpid indicates the process exited owing to
a signal.