Security update for python-Jinja2 (important)

This update for python-Jinja2 fixes the following issues:

Update to version 2.8:

• Added target parameter to urlize function.

• Added support for followsymlinks to the file system loader.

• The truncate filter now counts the length.

• Added equalto filter that helps with select filters.

• Changed cache keys to use absolute file names if available instead of
  load names.

• Fixed loop length calculation for some iterators.

• Changed how Jinja2 enforces strings to be native strings in Python 2 to
  work when people break their default encoding.

• Added :func:make_logging_undefined which returns an undefined
  object that logs failures into a logger.

• If unmarshalling of cached data fails the template will be reloaded now.

• Implemented a block set tag.

• Default cache size was incrased to 400 from a low 50.

• Fixed is number test to accept long integers in all Python versions.

• Changed is number to accept Decimal as a number.

• Added a check for default arguments followed by non-default arguments.
  This change makes {% macro m(x, y=1, z) %}...{% endmacro %} a syntax
  error. The previous behavior for this code was broken anyway (resulting
  in the default value being applied to y).

• Add ability to use custom subclasses of
  jinja2.compiler.CodeGenerator and jinja2.runtime.Context by
  adding two new attributes to the environment (code_generator_class and
  context_class) (pull request #404).

• added support for context/environment/evalctx decorator functions on the
  finalize callback of the environment.

• escape query strings for urlencode properly. Previously slashes were
  not escaped in that place.

• Add ‘base’ parameter to ‘int’ filter.

• Update to 2.7.3 (boo#858239, CVE-2014-0012)