Fix uri for change in case in response

In python3, response fields are title cased whereas in python2 they were
not.  We return these fields to the module's caller so we need to
normalize all of them to be lower case.

This reverts the lowercase check from 454f741ef5
as that one was only targetted as a single field.

lib/ansible/modules/network/basics/uri.py

@@ -437,9 +437,11 @@ def main():
 
     # Transmogrify the headers, replacing '-' with '_', since variables dont
     # work with dashes.
+    # In python3, the headers are title cased.  Lowercase them to be
+    # compatible with the python2 behaviour.
     uresp = {}
     for key, value in six.iteritems(resp):
-        ukey = key.replace("-", "_")
+        ukey = key.replace("-", "_").lower()
         uresp[ukey] = value
 
     try:
@@ -449,14 +451,8 @@ def main():
 
     # Default content_encoding to try
     content_encoding = 'utf-8'
-    content_type_key = None
+    if 'content_type' in uresp:
-    for key in uresp:
+        content_type, params = cgi.parse_header(uresp['content_type'])
-        # Py2: content_type; Py3: Content_type
-        if 'content_type' == key.lower():
-            content_type_key = key
-            break
-    if content_type_key is not None:
-        content_type, params = cgi.parse_header(uresp[content_type_key])
         if 'charset' in params:
             content_encoding = params['charset']
         u_content = to_text(content, encoding=content_encoding)