Add compiler warning flags and fix compile warning

Add compiler warning flags and fix compile warning

[Problem]
In case of adding compiler warning, there is one build error in class NetherCynaraBackend

The order of member variable between cynaraConfig and cynaraResult in class declaration is different from order of enumeration in constructor

* class declaration
class NetherCynaraBackend : public NetherPolicyBackend
{
   ....
   private:
   ....

          cynara_async_configuration *cynaraConfig;
          std::vector<u_int32_t> responseQueue;
          int cynaraResult;
}

* constructor
NetherCynaraBackend::NetherCynaraBackend(const NetherConfig &netherConfig)
             : NetherPolicyBackend(netherConfig), currentCynaraDescriptor(0),
             cynaraLastResult(CYNARA_API_UNKNOWN_ERROR), CynaraConfig(nullptr)

[Fix]
Change order between cynaraResult and cynaraConfig of class declaration

Change-Id: Ia03b10a33ee6b025ee28d76b82035e8f9cfb68d1
Signed-off-by: seong.chung <seong.chung@samsung.com>