controller: datastore: do not delete instances from nodes blindly
controller: datastore: do not delete instances from nodes blindly

If we haven't yet gotten a node stat for an instances being deleted
it will not be in the nodes map.  Check for existence of a NodeId
prior to deleting.

Signed-off-by: Kristen Carlson Accardi <047ff8258f0113ece56e5e2fe9e0d987b14c4333@linux.intel.com>

jorgevgut/ciao,chavafg/ciao,markdryan/ciao,wcwxyz/ciao,rbradford/ciao,ciao-project/ciao,matthewrsj/ciao,matthewrsj/ciao,kaccardi/ciao,mrkz/ciao,erick0z/ciao,mrkz/ciao,ciao-project/ciao,tpepper/ciao,obedmr/ciao,leoswaldo/ciao,leoswaldo/ciao,01org/ciao,tpepper/ciao,chavafg/ciao,markdryan/ciao,rbradford/ciao,wcwxyz/ciao,matthewrsj/ciao,mrkz/ciao,erick0z/ciao,obedmr/ciao,mcastelino/ciao,mcastelino/ciao,erick0z/ciao,jorgevgut/ciao,mcastelino/ciao,wcwxyz/ciao,leoswaldo/ciao,01org/ciao,kaccardi/ciao,obedmr/ciao,jorgevgut/ciao,tpepper/ciao