Fix infinite loop in ServerDescriptor#updateAdsPropertiesWithServerProperties

Test case:

1. Create initial instance as stand-alone (no replication or ADS);
2. Create second instance as part of replication toplogy, specifying instance created in step 1.

Configuration of instance 2 hangs in registering server with ADS.

Works after this change; however, now get on OS X:

$ ./setup
Launching graphical setup...
2007-08-27 12:11:07.058 java[3932] CFLog (0): CFMessagePort: bootstrap_register(): failed 1103 (0x44f), port = 0x12503, name = 'java.ServiceProvider'
See /usr/include/servers/bootstrap_defs.h for the error codes.
2007-08-27 12:11:07.061 java[3932] CFLog (99): CFMessagePortCreateLocal(): failed to name Mach port (java.ServiceProvider)