core.c: Cosmetic formatting changes

Signed-off-by: Hal Rosenstock <hal@mellanox.com>
plugin: Fix 'subnet_prefix' endianness

The issue was pointed out by Sasha, while trying
to use subnet_prefix that is stored in SMDB subnet
options table.

Signed-off-by: Ilya Nelkenbaum <ilyan@mellanox.com>
Signed-off-by: Hal Rosenstock <hal@mellanox.com>