tls_process: don't set variable that's never read

tls_process: don't set variable that's never read

Found by the clang static analyzer: the state_change variable is set,
but never read afterwards.  This code has been like this since 2005,
makes sense without setting state_change to true, and has worked fine
for the past 11 years.

Signed-off-by: Steffan Karger <steffan.karger@fox-it.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1480344801-27855-1-git-send-email-steffan.karger@fox-it.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg13260.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>