MINOR: server: pass adm and op cause to srv_update_status()

MINOR: server: pass adm and op cause to srv_update_status()

Operational and administrative state change causes are not propagated
through srv_update_status(), instead they are directly consumed within
the function to provide additional info during the call when required.

Thus, there is no valid reason for keeping adm and op causes within
server struct. We are wasting space and keeping uneeded complexity.

We now exlicitly pass change type (operational or administrative) and
associated cause to srv_update_status() so that no extra storage is
needed since those values are only relevant from srv_update_status().