Remove spurious `changed` state on iam_policy module (#4381)

Due to a mixup of the group/role/user and policy names, policies with
the same name as the group/role/user they are attached to would never be
updated after creation. To fix that, we needed two changes to the logic
of policy comparison:

- Compare the new policy name to *all* matching policies, not just the
  first in lexicographical order
- Compare the new policy name to the matching ones, not to the IAM
  object the policy is attached to

lib/ansible/modules/cloud/amazon/iam_policy.py

@@ -137,7 +137,7 @@ def user_action(module, iam, name, policy_name, skip, pdoc, state):
     current_policies = [cp for cp in iam.get_all_user_policies(name).
                                         list_user_policies_result.
                                         policy_names]
-    pol = ""
+    matching_policies = []
     for pol in current_policies:
       '''
       urllib is needed here because boto returns url encoded strings instead
@@ -145,13 +145,13 @@ def user_action(module, iam, name, policy_name, skip, pdoc, state):
       if urllib.unquote(iam.get_user_policy(name, pol).
                         get_user_policy_result.policy_document) == pdoc:
         policy_match = True
-        break
+        matching_policies.append(pol)
 
     if state == 'present':
       # If policy document does not already exist (either it's changed
       # or the policy is not present) or if we're not skipping dupes then
       # make the put call.  Note that the put call does a create or update.
-      if (not policy_match or not skip) and pol != name:
+      if not policy_match or (not skip and policy_name not in matching_policies):
         changed = True
         iam.put_user_policy(name, policy_name, pdoc)
     elif state == 'absent':
@@ -189,18 +189,18 @@ def role_action(module, iam, name, policy_name, skip, pdoc, state):
       module.fail_json(msg=e.message)
 
   try:
-    pol = ""
+    matching_policies = []
     for pol in current_policies:
       if urllib.unquote(iam.get_role_policy(name, pol).
                         get_role_policy_result.policy_document) == pdoc:
         policy_match = True
-        break
+        matching_policies.append(pol)
 
     if state == 'present':
       # If policy document does not already exist (either it's changed
       # or the policy is not present) or if we're not skipping dupes then
       # make the put call.  Note that the put call does a create or update.
-      if (not policy_match or not skip) and pol != name:
+      if not policy_match or (not skip and policy_name not in matching_policies):
         changed = True
         iam.put_role_policy(name, policy_name, pdoc)
     elif state == 'absent':
@@ -234,20 +234,19 @@ def group_action(module, iam, name, policy_name, skip, pdoc, state):
     current_policies = [cp for cp in iam.get_all_group_policies(name).
                                         list_group_policies_result.
                                         policy_names]
-    pol = ""
+    matching_policies = []
     for pol in current_policies:
       if urllib.unquote(iam.get_group_policy(name, pol).
                         get_group_policy_result.policy_document) == pdoc:
         policy_match = True
-        if policy_match:
-          msg=("The policy document you specified already exists "
-               "under the name %s." % pol)
-        break
+        matching_policies.append(pol)
+        msg=("The policy document you specified already exists "
+             "under the name %s." % pol)
     if state == 'present':
       # If policy document does not already exist (either it's changed
       # or the policy is not present) or if we're not skipping dupes then
       # make the put call.  Note that the put call does a create or update.
-      if (not policy_match or not skip) and pol != name:
+      if not policy_match or (not skip and policy_name not in matching_policies):
         changed = True
         iam.put_group_policy(name, policy_name, pdoc)
     elif state == 'absent':