OpsGenie state returns with incorrect type for changes

Description of Issue

'changes' should be a dictionary, e.g.

      ID: monitoring-http-IPTPRDORC101-81-alert-opsgenie-close
Function: opsgenie.close_alert
    Name: aurizon-ndc-b1-monitor-http-IPTPRDORC101-81-alert-opsgenie
  Result: False
 Comment: An exception occurred in this state: 'Changes' should be a dictionary.
 Changes:   

The state returns False even though it has succeeded in talking to the OpsGenie API. Hence dependent states can't reliably use True/False return from the opsgenie states.

Simple diff that fixes this is,

--- opsgenie.py.orig 2019-12-09 15:50:35.283153678 +1000
+++ opsgenie.py 2019-12-09 15:47:55.242250951 +1000
@@ -75,7 +75,7 @@
ret = {
'result': '',
'name': '',

•    'changes': '',
  

•    'changes': {},
     'comment': ''
  

  }

Setup

2019.2.2

Steps to Reproduce Issue

Try to use any OpsGenie state, e.g. create_alert or close_alert

Versions Report

$ salt --versions-report
Salt Version:
Salt: 2019.2.2

Dependency Versions:
cffi: 1.6.0
cherrypy: Not Installed
dateutil: 1.5
docker-py: 1.10.6
gitdb: 0.6.4
gitpython: 1.0.1
ioflo: 1.3.8
Jinja2: 2.7.2
libgit2: 0.26.3
libnacl: 1.6.1
M2Crypto: 0.31.0
Mako: 0.8.1
msgpack-pure: Not Installed
msgpack-python: 0.5.6
mysql-python: 1.2.5
pycparser: 2.14
pycrypto: 2.6.1
pycryptodome: 3.7.3
pygit2: 0.26.4
Python: 2.7.5 (default, Aug 7 2019, 00:51:29)
python-gnupg: 0.4.3
PyYAML: 3.11
PyZMQ: 15.3.0
RAET: Not Installed
smmap: 0.9.0
timelib: Not Installed
Tornado: 4.2.1
ZMQ: 4.1.4

System Versions:
dist: centos 7.7.1908 Core
locale: UTF-8
machine: x86_64
release: 3.10.0-957.27.2.el7.x86_64
system: Linux
version: CentOS Linux 7.7.1908 Core

Start in opsgenie.py and inspect the return structure used by the create_alert and close_alert states. Reproduce the issue with an OpsGenie state, then verify that a successful API call returns a dictionary for Changes and allows dependent states to use the result reliably.