MFH: r404751

irc/inspircd: Update to 2.0.20

Fix default config file path to sample configs and add rc script chdir
so these relative paths work. This makes it easier to get a new install
up and running.

Security: b808c3a8-ae30-11e5-b864-14dae9d210b8
Approved by: ports-secteam (with hat)