Need to check if the alps odls component has already
read the rdma creds from alps. Its okay to ask apshepherd
multiple times for rdma creds, but opal_setenv gets
a bit picky about this. Rather than check for the OPAL_EXISTS
return value from opal_setenv, for now just check with
a static variable whether or not orte_odls_alps_get_rdma_creds
has already been successfully called before.
Would be nice to have an opal_getenv function for checking
if an env. variable had already been set by opal_putenv.
fd807aee69