Avoids potential endless loops with non-blocking I/O.

fixes "gotd: unexpected imsg 40" in logs

Fixes timeout setting used by http notification helper during tests.

Patch by op@, committing on his behalf and will be adding fixes on top

Remove got_pathlist_append(). This leaves got_pathlist_insert() to add items to a pathlist, making it very easy to swap got_pathlist from a TAILQ to a RB_TREE. Patch by Kyle Ackerman

Instead of sorting refs by name and then hunting for the youngest commits in that list, obtain an appropriately sorted list via got_ref_cmp_by_commit_timestamp_descending and then pick the first ref from this list. And in the case were we already know which ref to check, just open this ref directly instead of listing all the refs. Easier to read and should improve performance in both cases. ok op, jamsek

ok jamsek, stsp

If a non-default config filepath is specified with -f, it is effectively ignored as child processes always either parse the default config file (/etc/gotwebd.conf) if it exists, or use defaults. Options specified in the config file used by server procs (e.g., chroot, user) are ignored. If -f is used with a non-default config file, pass it to child procs. ok stsp@

When a reference exists on the server but not locally, 'got send' could fail to ignore this reference as intended, raising an error instead. Add a test case for this isssue.

In addition to the previous commit [c450903bc2] that plugged fetch and send leaks, free what would be the path entry's path member, which is leaked when attempting to add a duplicate. And in the fetch case, free refname and id when got_pathlist_insert() returns err. ok stsp@

Patch by op@, who is at the wrong computer right now

Patch by: Kyle Ackerman