ioc: fix dbLoadGroups command.

Calling GroupConfigProcessor().loadConfigFiles() reads and clears
config.groupConfigFiles, and loads the JSON files before iocInit. When
loadConfigFiles() is called again from an init-hook,
config.groupConfigFiles is empty, and no JSON files are actually read,
so no groups in those files are loaded.

This change removes error messages at the point where dbLoadGroup is
called; errors are now displayed only during iocInit.

ioc/groupsourcehooks.cpp

@@ -42,7 +42,6 @@ namespace ioc {
 static
 void dbLoadGroupCmd(const char* jsonFileName, const char *macros) {
     iocshSetError(!!dbLoadGroup(jsonFileName, macros));
-    GroupConfigProcessor().loadConfigFiles();
 }
 
 /**