znc: bump to version 1.6.1

Bump to release tarball version.
Add hash file.
Update and rework time.h patch for upstream inclusion (hopefully) by
splitting the CSocket patch out.
(https://github.com/znc/znc/pull/1021

)

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>