packages ubuntu: use specific vendor profile

When executing make upload on recent debian/unstable, it causes an error
such as "E: bad-distribution-in-changes-file XXX".

It means that lintian doesn't know XXX because default profile is
set to "debian". In this case, it is better to use "ubuntu" profile.

packages/ubuntu/upload.rb

@@ -196,7 +196,7 @@ def upload(code_name, mysql_short_version, mysql_version)
                     "-i", "-e",
                     "s,MYSQL_VERSION\\|MARIADB_VERSION,#{mysql_version},",
                     "debian/control")
-        run_command("debuild", "-S", "-sa", "-pgpg2", "-k#{@pgp_sign_key}")
+        run_command("debuild", "--set-envvar=LINTIAN_PROFILE=ubuntu", "-S", "-sa", "-pgpg2", "-k#{@pgp_sign_key}")
         if @use_pbuilder
           run_command("pbuilder-dist", code_name, "build",
                       "../#{deb_package_name}_#{deb_version}.dsc")