core,log: fix warnings with -Wswitch-enum

mm-log.c: In function ‘glib_to_syslog_priority’:
  mm-log.c:99:5: warning: enumeration value ‘G_LOG_FLAG_RECURSION’ not handled in switch [-Wswitch-enum]
     99 |     switch (level) {
        |     ^~~~~~
  mm-log.c:99:5: warning: enumeration value ‘G_LOG_FLAG_FATAL’ not handled in switch [-Wswitch-enum]
  mm-log.c:99:5: warning: enumeration value ‘G_LOG_LEVEL_INFO’ not handled in switch [-Wswitch-enum]
  mm-log.c:99:5: warning: enumeration value ‘G_LOG_LEVEL_MASK’ not handled in switch [-Wswitch-enum]

src/mm-log.c

@@ -107,10 +107,15 @@ glib_to_syslog_priority (GLogLevelFlags level)
         return LOG_WARNING;
     case G_LOG_LEVEL_MESSAGE:
         return LOG_NOTICE;
+    case G_LOG_LEVEL_INFO:
+        return LOG_INFO;
     case G_LOG_LEVEL_DEBUG:
         return LOG_DEBUG;
+    case G_LOG_LEVEL_MASK:
+    case G_LOG_FLAG_FATAL:
+    case G_LOG_FLAG_RECURSION:
     default:
-        return LOG_INFO;
+        g_assert_not_reached ();
     }
 }