oc_core: randomize uuid before use
oc_core: randomize uuid before use

Initialize the uuid buffer with random values before
passing it to oc_gen_uuid().

Signed-off-by: Naveen Kaje <79e427f88b1293e6ef90566b3bd0a85565336125@juul.com>

mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core