revert apache::mod::passenger default parameters for RedHat

The prior commit modified the default parameters for mod::passenger for
RedHat, hardcoding paths related to the installed package; these changes
were unnecessary and are being reverted.

The changes were originally prompted by (new) spec acceptance temps
leveraging passenger-status (to verify that passenger is running); these
tests were not working under RedHat; revisiting with the original
default parameters revealed that the RedHat tests were misconfigured
(the required PASSENGER_TMPDIR environment was not being set), so those
have been corrected.

Also, spec/class tests have be reverted to reflect the (reverted)
expected parameters.
turning MaxKeepAliveRequests into a variable
introducing new setting to documentation
renaming variable to be inline with other variables

maxkeepaliverequests => max_keepalive_requests
Don't include the NameVirtualHost directives in apache >= 2.4, and add tests for this that will at least work with Ubuntu 13.10 and Ubuntu 14.04.

Tests will still work anywhere with apache < 2.4, but haven't been updated to support RHEL7 yet.
Fix platform for centos-6.5

It looks like an accidental replace from 64 to 65 in the platform.
Merge pull request #708 from mhaskel/NameVirtualHost-deprecation

Don't include the NameVirtualHost directives in apache >= 2.4, and add t...
Merge pull request #698 from jonoterc/fix_passenger_redhat

revert apache::mod::passenger default parameters for RedHat
Merge pull request #710 from ekohl/patch-1

Fix platform for centos-6.5
Merge pull request #703 from attachmentgenie/MaxKeepAliveRequests

turning MaxKeepAliveRequests into a variable
 Configure Passenger in separate .conf file on Debian so PassengerRoot isn't lost

The changes in 005bf615c are also necessary for Ubuntu 14.04 which now
ships Passenger 4.x