Short circuit root test for building Debian packages

Origin: vendor
Forwarded: not-needed
Last-Update: 2020-04-13

  * Patch install.Installer class not to error out when subclassed as
    DebianInstaller from dh-python

flit/install.py

@@ -109,7 +109,8 @@ class Installer(object):
 
         if (hasattr(os, 'getuid') and (os.getuid() == 0) and
                 (not os.environ.get('FLIT_ROOT_INSTALL'))):
-            raise RootInstallError
+            if type(self).__name__ != 'DebianInstaller':
+                raise RootInstallError
 
         if user is None:
             self.user = self._auto_user(python)