The opal_gethostname() function provides a more robust mechanism
to retrieve the hostname than gethostname(), which can return
results that are not null-terminated, and which can vary in its
behavior from system to system.
opal_gethostname() just returns the value in opal_process_info.nodename;
this is populated in opal_init_gethostname() inside opal_init.c.
-Changed all gethostname calls in opal subtree to opal_gethostname
-Changed all gethostname calls in orte subtree to opal_gethostname
-Changed all gethostname calls in ompi subdir to opal_gethostname
-Changed all gethostname calls in oshmem subdir to opal_gethostname
-Changed opal_if.c in test subdir to use opal_gethostname
-Changed opal_init.c to include opal_init_gethostname. This function
returns an int and directly sets opal_process_info.nodename per
jsquyres' modifications.
Relates to open-mpi#6801
Signed-off-by: Charles Shereda <cpshereda@lanl.gov>
