#42 generates "Unescaped left brace in regex is deprecated" warnings under perl-5.22

[Mark Grimes]

Left braces must be escaped under Perl 5.22. This impacts serveral of the service scripts. The attached patches correct amavis, http, postifx and secure. There may be others.

Reported on the mailing list:

https://sourceforge.net/p/logwatch/mailman/message/34334890/

[Stefan Jakobs]

Thanks for reporting. Fixed.