osdict: Raise exception on get_location failure

It's better to error immediately if we know this won't work

virt-install

@@ -444,12 +444,8 @@ def build_installer(options, guest):
     if options.os_variant.install == "location":
         if not options.location:
             location = guest.osinfo.get_location(guest.os.arch)
-            if not location:
-                logging.debug(_("No location could be guessed from osinfo-db "
-                    "and the installation cannot proceed"))
-                # This triggers an error in validate_required_options
-                return None
-            logging.debug("Generated default libosinfo '--location %s'", location)
+            logging.debug(
+                    "Generated default libosinfo '--location %s'", location)
             options.location = location
     elif options.os_variant.install == "cdrom":
         pass

virtinst/osdict.py

@@ -486,16 +486,14 @@ class _OsVariant(object):
 
         treelist = self._os.get_tree_list()
         if treelist.get_length() < 1:
-            logging.error(
-                _("%s does not have a URL location"), self.name)
-            return None
+            raise RuntimeError(
+                _("%s does not have a URL location") % self.name)
 
         filtered_treelist = treelist.new_filtered(treefilter)
         if filtered_treelist.get_length() < 1:
-            logging.error(
-                _("%s does not have a URL location for the %s architecture"),
-                  self.name, arch)
-            return None
+            raise RuntimeError(
+                _("%s does not have a URL location for the %s architecture") %
+                (self.name, arch))
 
         # Some distros have more than one URL for a specific architecture,
         # which is the case for Fedora and different variants (Server,