restore initial json parsing attempt to loader

fixes issues with extra vars json strings not being parsed correctly by the yaml parser

lib/ansible/parsing/dataloader.py

@@ -72,8 +72,12 @@ class DataLoader():
         Creates a python datastructure from the given data, which can be either
         a JSON or YAML string.
         '''
-
-        # YAML parser will take JSON as it is a subset.
+        new_data = None
+        try:
+            # we first try to load this data as JSON
+            new_data = json.loads(data)
+        except:
+            # must not be JSON, let the rest try
             if isinstance(data, AnsibleUnicode):
                 # The PyYAML's libyaml bindings use PyUnicode_CheckExact so
                 # they are unable to cope with our subclass.
@@ -90,6 +94,7 @@ class DataLoader():
             if isinstance(data, AnsibleUnicode):
                 new_data = AnsibleUnicode(new_data)
                 new_data.ansible_pos = data.ansible_pos
+
         return new_data
 
     def load_from_file(self, file_name):