added initial self._mirrors

fixed found_mirrors with 'https://releases.ubuntu.com/' if there's 'it1.mirror.vhosting-it.com'

(it's a quick fix, it will be fix when I make auto-compile.download.toml)

uitwww/download.py

@@ -37,6 +37,8 @@ CACHE_FILE_VERSION = 1
 class Downloads:
 
     def __init__(self, data_path):
+        # init _mirrors
+        self._mirrors = None
         # Load the configuration
         path = UITWWW_DIR + CONFIG_FILE
         self.config = toml.load(
@@ -61,7 +63,7 @@ class Downloads:
     @property
     def mirrors(self):
         """Get a list of CD mirrors needed by the website"""
-        if not hasattr(self, "_mirrors"):
+        if not hasattr(self, "_mirrors") or self._mirrors is None:
             if self._cache is not None:
                 self._mirrors = self._cache["mirrors"]
             else:
@@ -70,6 +72,8 @@ class Downloads:
                     found_mirrors = list(sorted(launchpad.get_cdimage_mirrors(
                         distro, self.config["mirrors"]["country"]
                     )))
+                    if "it1.mirror.vhosting-it.com" in found_mirrors[0]:
+                        found_mirrors = ["https://releases.ubuntu.com/"]
                     if found_mirrors:
                         self._mirrors[distro] = found_mirrors
                 if not self._mirrors: