Merge branch 'gs/test-unset-xdg-cache-home' into maint

Test update.

* gs/test-unset-xdg-cache-home:
  test-lib.sh: unset XDG_CACHE_HOME

t/test-lib.sh

@@ -116,6 +116,7 @@ unset VISUAL EMAIL LANGUAGE COLUMNS $("$PERL_PATH" -e '
 	my @vars = grep(/^GIT_/ && !/^GIT_($ok)/o, @env);
 	print join("\n", @vars);
 ')
+unset XDG_CACHE_HOME
 unset XDG_CONFIG_HOME
 unset GITPERLLIB
 GIT_AUTHOR_EMAIL=author@example.com