tools (config): show a warning when no config file has been found + don't use hardcoded filename in fixConfigOption

sat/tools/config.py

@@ -58,7 +58,9 @@ def fixConfigOption(section, option, value, silent=True):
             break
     if not target_file:
         # ... otherwise we create a new config file for that user
-        target_file = BaseDirectory.save_config_path("sat") + "/sat.conf"
+        target_file = (
+            f"{BaseDirectory.save_config_path(C.APP_NAME_FILE)}/{C.APP_NAME_FILE}.conf"
+        )
     if section and section.upper() != DEFAULTSECT and not config.has_section(section):
         config.add_section(section)
     config.set(section, option, value)
@@ -84,9 +86,14 @@ def parseMainConf(log_filenames=False):
         log.error(_("Can't read main config: {msg}").format(msg=e), exc_info=True)
     else:
         if log_filenames:
-            log.info(
-                _("Configuration was read from: {filenames}").format(
-                    filenames=', '.join(filenames)))
+            if filenames:
+                log.info(
+                    _("Configuration was read from: {filenames}").format(
+                        filenames=', '.join(filenames)))
+            else:
+                log.warning(
+                    _("No configuration file found, using default settings")
+                )
 
     return config