fix "stack/caucase: Fix md5 change detection"

Make the md5 detection fix python3 compatible.

Fixes 4e5a9ee4

stack/caucase/buildout.hash.cfg

@@ -15,4 +15,4 @@
 
 [caucase-jinja2-library]
 filename = caucase.jinja2.library
-md5sum = b3ee1414719f8a24790ae324ca023066
+md5sum = a5c7a46c6fb85aa22a371d9d2cd9e57e

stack/caucase/caucase.jinja2.library

@@ -133,7 +133,7 @@ recipe = plone.recipe.command
 checksum-file = '{{ template }}.md5'
 command =
   set -e
-  md5_current=$(${buildout:executable} -c "import hashlib ; print hashlib.md5(open('{{ template }}', 'rb').read()).hexdigest()")
+  md5_current=$(${buildout:executable} -c "from __future__ import print_function ; import hashlib ; print(hashlib.md5(open('{{ template }}', 'rb').read()).hexdigest())")
   md5_old=$([ -f ${:checksum-file} ] && cat ${:checksum-file} || echo none)
   if [ "$md5_current" != "$md5_old" ] || [ ! -f '{{ csr }}' ] || [ ! -f '{{ key }}' ] ; then
     '{{ buildout_bin_directory }}/caucase-rerequest' --template '{{ template }}' --csr '{{ csr }}' --key '{{ key }}'