Merge branch 'jk/quote-env-path-list-component' into maint

A recent update to receive-pack to make it easier to drop garbage objects made it clear that GIT_ALTERNATE_OBJECT_DIRECTORIES cannot have a pathname with a colon in it (no surprise!), and this in turn made it impossible to push into a repository at such a path. This has been fixed by introducing a quoting mechanism used when appending such a path to the colon-separated list. * jk/quote-env-path-list-component: t5615-alternate-env: double-quotes in file names do not work on Windows t5547-push-quarantine: run the path separator test on Windows, too tmp-objdir: quote paths we add to alternates alternates: accept double-quoted paths