MODULES-1382: support multiple access log directives

MODULES-1382: https://tickets.puppetlabs.com/browse/MODULES-1382
This being easier to read/simpler is a matter of opinion, I prefer ternary operators because I think they're easier to read.  That being said, I don't mind changing it.  I think later on in the template though <%= env %> could result to the literal 'nil' or 'undef' for older versions of ruby if log['env'] (and therefore env) was unset, wouldn't it?  The purpose of setting it to if log['env'] was undefined was to ensure the template was clean on output.