zbeacon: Use zinterface_list() in s_get_interface()
Fix memory leak in zinterface_list() for Windows.
Fix an infinite recursion in zsys_init().

zsys_init() was getting in an infinite recursion if called with any of
the following ENVVARS set:
- ZSYS_INTERFACE
- ZSYS_LOGIDENT
- ZSYS_LOGSENDER
Merge pull request #588 from ahhentz/zinterface

zbeacon: Use zinterface_list() in s_get_interface()
Merge pull request #589 from ahhentz/bugfix

Some bugfixes