postgresql: security bump to version 9.4.6

Fixes:
CVE-2016-0766 - privilege escalation issue for users of PL/Java.
CVE-2016-0773 - issue with regular expression (regex) parsing. Prior
code allowed users to pass in expressions which included out-of-range
Unicode characters, triggering a backend crash. This issue is critical
for PostgreSQL systems with untrusted users or which generate regexes
based on user input.

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