SSL connect error since using curl in GnuTLS flavor

[Gionn]

As per this https://support.zabbix.com/browse/ZBX-727, the zabbix package in Trusty can't be used to monitor https endpoint since certs validation always fail with a SSL connect error.

The error happens when zabbix server/proxy is compiled with libcurl4-gnutls-dev and it goes away if you recompile zabbix with libcurl4-openssl-dev.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: zabbix-agent 1:2.2.2+dfsg-1ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-32.57-generic 3.13.11.4
Uname: Linux 3.13.0-32-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.5
Architecture: amd64
Date: Wed Oct 15 16:31:59 2014
InstallationDate: Installed on 2014-07-28 (79 days ago)
InstallationMedia: Ubuntu-Server 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.3)
SourcePackage: zabbix
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.