adding apache2 digest authentication option support + 3 misc fixes

misc fixes related to:
- make log dir permissions as per common setup for /var/log/<dir> i.e. 755
- error encountered during chef runs: "invalid regular expression; there's
  no previous pattern, to which '{' would define cardinality at 1: /{|}/"
- provide attribute to be able to avoid duplicate NameVirtualHost directive
  so that one does not see "NameVirtualHost *:80 has no VirtualHosts"
  during apache2 startup.