includes: wrap missing include file exception

The common case that an include file cannot be found is now wrapped into
a LoadConfigException. By that, the user gets a more meaningful error
message on the console (instead of a stacktrace).

Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

kas/includehandler.py

@@ -186,7 +186,11 @@ class IncludeHandler:
 
             missing_repos = []
             configs = []
-            current_config = load_config(filename)
+            try:
+                current_config = load_config(filename)
+            except FileNotFoundError:
+                raise LoadConfigException('Configuration file not found',
+                                          filename)
             if not isinstance(current_config, Mapping):
                 raise IncludeException('Configuration file does not contain a '
                                        'dictionary as base type')