added logic to call exit(0) only when there are 2..n ArkoudaServerDaemons

[hokiegeek2]

This PR partially address #1694 by preventing invocation of the Chapel exit(0) function, which is known to fail on certain Cray machines, in the default arkouda_server config where there is 1 ArkoudaServerDaemon.

The root cause will be addressed in another issue and PR