ansible: move the RHEL lockfile to /var/run/edeploy and add tmpfiles.d configuration for RHEL7+

This commit fixes: https://github.com/enovance/edeploy/issues/159

With RHEL7+ /var/run is now tmpfs and gets recreated on reboot.  The default
permissions for /var/run/httpd doesn't allow httpd (once it's dropped root
privileges) to write to /var/run/httpd so we'll use a dedicated directory which
httpd/edeploy can write to (/var/run/edeploy)

/etc/tmpfiles.d/edeploy.conf ensures that systemd automatically creates
/var/run/edeploy and that httpd can write to that file.