dont break everything when one of the vars in inject does not template…

dont break everything when one of the vars  in inject does not template correctly, wait till its used

lib/ansible/utils/template.py

@@ -188,7 +188,11 @@ class _jinja2_vars(object):
         if isinstance(var, dict) and varname == "vars" or isinstance(var, HostVars):
             return var
         else:
-            return template(self.basedir, var, self.vars, fail_on_undefined=self.fail_on_undefined)
+            try:
+                return template(self.basedir, var, self.vars, fail_on_undefined=self.fail_on_undefined)
+            except:
+                raise KeyError("undefined variable: %s" % varname)
+
 
     def add_locals(self, locals):
         '''