Adding jinja2 for templating config files.

The trove project generates configuration files for installation
of datastore services, and modifies said files upon resizes of
servers, and this is templated and generated via jinja2.

Change-Id: Ifa2aa225b1b0739979a15b3a8e75944567e3b577

requirements.txt

@@ -18,6 +18,7 @@ greenlet>=0.3.2
 happybase>=0.4
 httplib2
 iso8601>=0.1.4
+jinja2
 jsonrpclib
 jsonschema>=1.0.0,!=1.4.0,<2
 kazoo>=0.9,<=1.1