chg: remove manual reload logic chgserver now validates and reloads configs automatically. Manually reloading is no longer necessary. Besides, we are deprecating pid files since the server will periodically check its ownership of the socket file and exit if it does not own the socket file any longer, which works more reliable than a pid file. This patch removes the SIGHUP reload logic from both chg server and client.

chg: use --daemon-postexec chdir:/ instead of --cwd / The chgserver is designed to load repo config from current directory. "--cwd /" will prevent chgserver from loading repo config and generate a wrong confighash, which will result in a redirect loop. This patch removes "--cwd /" and uses "--daemon-postexec chdir:/" instead.

serve: add chdir command for --daemon-postexec For chgserver, it probably needs a chdir to /. This patch adds chdir command support for --daemon-postexec so chg client can make use of it.

serve: accept multiple values for --daemon-postexec The next patch will add another postexec command: chdir, which can be used together with unlink. This patch changes the option type of --daemon-postexec from string to list to accept multiple commands. The error message of invalid --daemon-postexec value is also changed to include the actual invalid value.