removal of unrequested json snippet '"server-groups" => undefined' postpended to operation responses via cli

When submitting operations to as7 via CLI sometimes and extra ["server-groups" => undefined] string is post-pended to the response. The result is still valid JSON it appears, but the results are potentially confusing to external json integrators.

To reproduce:

• run AS7 via domain.sh to run HostController.
• login
• submit the following operation:
  /host=master/core-service=platform-mbean/type=threading/:read-resource(recursive=true,proxies=false,include-runtime=true,include-defaults=true)
• Look at the result returned:
  {
  "outcome" => "success",
  "result" => { "all-thread-ids" => [ 2173L, 2172L, 2171L, 51L, 50L, 49L, 48L, 45L, 44L, 43L, 42L, 41L, 40L, 39L, 38L, 37L, 36L, 35L, 34L, 33L, 32L, 31L, 30L, 29L, 28L, 27L, 26L, 25L, 24L, 23L, 22L, 21L, 19L, 18L, 17L, 16L, 15L, 14L, 13L, 12L, 11L, 8L, 4L, 3L, 2L, 1L ], "thread-contention-monitoring-supported" => true, "thread-cpu-time-supported" => true, "current-thread-cpu-time-supported" => true, "object-monitor-usage-supported" => true, "synchronizer-usage-supported" => true, "thread-contention-monitoring-enabled" => false, "thread-cpu-time-enabled" => true, "thread-count" => 46, "peak-thread-count" => 49, "total-started-thread-count" => 2168L, "daemon-thread-count" => 6, "current-thread-cpu-time" => 0L, "current-thread-user-time" => 0L }

  ,
  "server-groups" => undefined
  }