Bug Fix: Avatars do not display with account on a self-signed server

Avatars do not display with matrix.org account after trusting a self-signed certificate.
Fix: reenable trusting anchor certificates in addition to those passed in via the SecTrustSetAnchorCertificates API.

element-hq/element-ios#816

MatrixSDK/Utils/Media/MXMediaLoader.m

@@ -250,6 +250,8 @@ - (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticatio
         if (pinnedCertificates.count > 0)
         {
             SecTrustSetAnchorCertificates(protectionSpace.serverTrust, (__bridge CFArrayRef)pinnedCertificates);
+            // Reenable trusting anchor certificates in addition to those passed in via the SecTrustSetAnchorCertificates API.
+            SecTrustSetAnchorCertificatesOnly(protectionSpace.serverTrust, false);
         }
 
         SecTrustRef trust = [protectionSpace serverTrust];