Get rid of the jinja syntax checker.

There are two big reasons for doing so:
  - It relied on functions that were internal to ansible and whole behavior has now changed.
    The functions to get the extensions and filters from ansible can still be accessed after
    instantiating an object of the Templar class but the way that this loads variables has
    now changed and so we can't do the same sort of tests as we did previously without loading
    the entire variable context for the template file.
  - This test should now be achieved by running the relevant docker builds that test the templates
    can render correctly within the full context they need.

To catch errors faster we may want to add a jinja linter that does the rudimentry syntax checks
without needing to know about the ansible jinja filters and extensions that are available.

test.mk

 
 yml_files:=$(shell find . -name "*.yml")
 json_files:=$(shell find . -name "*.json")
-jinja_files:=$(shell find . -name "*.j2")
 # $(images) is calculated in the docker.mk file
 
 test: test.syntax test.edx_east_roles
 
-test.syntax: test.syntax.yml test.syntax.json test.syntax.jinja test.syntax.dockerfiles
+test.syntax: test.syntax.yml test.syntax.json test.syntax.dockerfiles
 
 test.syntax.yml: $(patsubst %,test.syntax.yml/%,$(yml_files))
 
@@ -18,11 +17,6 @@ test.syntax.json: $(patsubst %,test.syntax.json/%,$(json_files))
 test.syntax.json/%:
 	jsonlint -v $*
 
-test.syntax.jinja: $(patsubst %,test.syntax.jinja/%,$(jinja_files))
-
-test.syntax.jinja/%:
-	cd playbooks && python ../tests/jinja_check.py ../$*
-
 test.syntax.dockerfiles:
 	python util/check_dockerfile_coverage.py "$(images)"
 	

tests/jinja_check.py

-#!/usr/bin/env python
-import os
-import sys
-from jinja2 import FileSystemLoader
-from jinja2 import Environment as j
-from jinja2.exceptions import UndefinedError
-from ansible.utils.template import _get_filters, _get_extensions
-from yaml.representer import RepresenterError
-
-input_file = sys.argv[1]
-
-if not os.path.exists(input_file):
-    print('{0}: deleted in diff'.format(input_file))
-    sys.exit(0)
-
-# Setup jinja to include ansible filters
-j_e = j(trim_blocks=True, extensions=_get_extensions())
-j_e.loader = FileSystemLoader(['.', os.path.dirname(input_file)])
-j_e.filters.update(_get_filters())
-
-# Go ahead and catch errors for undefined variables and bad yaml
-# from `to_nice_yaml` ansible filter
-try:
-    j_e.from_string(file((input_file)).read()).render(func=lambda: None)
-except (UndefinedError, RepresenterError), ex:
-    pass
-except TypeError, ex:
-    if ex.message != 'Undefined is not JSON serializable':
-        raise Exception(ex.message)
-    pass
-print('{}: ok'.format(input_file))