Fix config issue loaded default config and ignoring overrides

When dlrn_url is overridden it is being ignored and instead the
default is used. This makes it that the passed config is honored.

Adds molecule test case to check vanilla invocation and test
that passed dlrn_url is honored - test cases brought from WIP
patch in [1].

Co-Authored-By: Sorin Sbarnea <ssbarnea@redhat.com>
[1] https://review.opendev.org/c/openstack/tripleo-repos/+/807700

Change-Id: Ie5354421a470e5a528307694b49f4e8d2bc24ddc

molecule/default/converge.yml

@@ -12,3 +12,13 @@
         # TODO: fix yum_config to correctly report changed state and uncomment
         # the line below which disables molecule idemptotence test.
         - molecule-idempotence-notest
+
+    - name: "Check get_hash"
+      tripleo.repos.get_hash:
+        release: master
+    - name: "Check get_hash with invalid url"
+      tripleo.repos.get_hash:
+        release: master
+        dlrn_url: 'https://httpbin.org/status/404'
+      register: result
+      failed_when: result is success

plugins/module_utils/tripleo_repos/get_hash/tripleo_hash_info.py

@@ -29,17 +29,23 @@ try:
     from ansible.module_utils.urls import open_url
 
     def http_get(url: str) -> Tuple[str, int]:
-        response = open_url(url, method='GET')
-        return (response.read(), response.status)
+        try:
+            response = open_url(url, method='GET')
+            return (response.read(), response.status)
+        except Exception as e:
+            return (str(e), -1)
 except ImportError:
     from urllib.request import urlopen
 
     def http_get(url: str) -> Tuple[str, int]:
         # https://stackoverflow.com/questions/35122232/urllib-request-urlopen-return-bytes-but-i-cannot-decode-it
-        response = urlopen(url)
-        return (
-            response.read().decode('utf-8'),
-            int(response.status))
+        try:
+            response = urlopen(url)
+            return (
+                response.read().decode('utf-8'),
+                int(response.status))
+        except Exception as e:
+            return (str(e), -1)
 
 __metaclass__ = type
 
@@ -145,10 +151,11 @@ class TripleOHashInfo:
             config_path = local_config
         else:
             logging.info("Using embedded config file")
-            return DEFAULT_CONFIG
+            loaded_config = DEFAULT_CONFIG
         logging.info("Using config file at %s", config_path)
-        with open(config_path, 'r') as config_yaml:
-            loaded_config = cls.load_yaml(config_yaml)
+        if config_path != '':
+            with open(config_path, 'r') as config_yaml:
+                loaded_config = cls.load_yaml(config_yaml)
         for k in CONFIG_KEYS:
             if k not in loaded_config:
                 error_str = (