Fix: services: Do not allow duplicate recurring op entries

Duplicate recurring operations silently replace each
other in a way that makes the original entry impossible
to cancel.  This can cause unexpected monitor failures to
occur  after resources were thought to have been stopped.
High: lrmd: Merge duplicate recurring monitor operations

Never allow two instances of the same recurring monitor operation
to exist in the lrmd.
Low: lrmd: recurring op merger regression tests