bug 6304

test33.1 recently broke. likely due to commit 03f8f1d3

Cleanup debug messages while here.

Remove stray #undef HAVE_SYS_SOCKET_H while here, this appears
to date back to before config.h was split off.

The slurm_addr_t typedef comes in from slurm.h already, so this
header is redundant.

NULL check is implied already, and this format is prevalent.

Also remove unnecessary casts while tidying up.

Change to plugrack_new_t to make sure every location is caught.

Remove plugrack_set_major_type().

Was never used to enable the paranoid behavior.

No functional change, aside from switching to __func__ in log messages.

Also switch to xmalloc pattern of:
    int *data = xmalloc(sizeof(*data));
while cleaning these up.

Remove now-unused variables missed in e7a34806/c10f2cf0.

Include explicit values so some can be removed in successive commits.