Added guard around adding a NULL object to an array

Author: kcharwood

AFNetworking/AFURLConnectionOperation.m

@@ -224,7 +224,8 @@ + (NSArray *)pinnedPublicKeys {
 
             SecKeyRef allowedPublicKey = SecTrustCopyPublicKey(allowedTrust);            
             NSCParameterAssert(allowedPublicKey);
-            [publicKeys addObject:(__bridge_transfer id)allowedPublicKey];
+            if(allowedPublicKey!=NULL)
+                [publicKeys addObject:(__bridge_transfer id)allowedPublicKey];
 
             CFRelease(allowedTrust);
             CFRelease(policy);