cmd/ocsplunk: switch to Arista fork
cmd/ocsplunk: switch to Arista fork

This fixes an incompatibility with go.uuid fixed at
https://github.com/aristanetworks/splunk-hec-go/commit/1bb755d91dae0f656c4c8621dea9b73a4532af1b

Change-Id: Id9e7b15aaf39b1b4d86426d62df7fc8f720f0946

aristanetworks/goarista,aristanetworks/goarista