EZP-21913: Fixed globals for scripts:

- updateniceurls.php
- runcronjobs.php
- ezasynchronouspublisher.php
- ezsubtreecopy.php
Doc EZP-21913: Add bc note on global use in bin/php scripts
Fix EZP-21914: reset ezcDb link from ezasynchronouspublishing.php
Merge pull request #832 from ezsystems/fix/EZP-21914-asyncpublishing_new_stack_db_link

Fix EZP-21914: reset ezcDb link from ezasynchronouspublishing.php
Merge pull request #831 from ezsystems/fix_EZP-21913_5.2_release

EZP-21913: Fixed globals for critical scripts