If dh_python2 supports --no-rewrite-shebang, use it

Signed-off-by: Dan Mick <dan.mick@inktank.com>
Makefile, conf/httpd: Collapse distro httpd confs into one:

- for all distros, use version >=2.4 for the new Require directive
- put WSGISocketPrefix in dynamically in Makefile

Signed-off-by: Dan Mick <dan.mick@inktank.com>
Mako is apparently on the trusty build machine but not production machines

Signed-off-by: Dan Mick <dan.mick@inktank.com>