DEVELOPERS: drop Jan Viktorin

Unfortunately, his e-mail is bouncing:

<viktorin@rehivetech.com>: host wes1-mx2.wedos.net[46.28.106.12] said: 550
    5.2.1 <viktorin@rehivetech.com>: Recipient address rejected: mailbox
    disabled - DEBUG: acc viktorin@rehivetech.com (in reply to RCPT TO command)

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

DEVELOPERS

@@ -1265,11 +1265,6 @@ F:	package/sysrepo/
 N:	Jan Pedersen <jp@jp-embedded.com>
 F:	package/zip/
 
-N:	Jan Viktorin <viktorin@rehivetech.com>
-F:	package/python-pexpect/
-F:	package/python-ptyprocess/
-F:	package/zynq-boot-bin/
-
 N:	Jarkko Sakkinen <jarkko.sakkinen@intel.com>
 F:	package/quota/