librtmp: Allow partial success for mbedtls

mbedtls_x509_crt_parse_path returns a positive number if it partially
succeeds and a negative number on complete failure. This changes the
positive result to no longer error and prevent TLS connections (OBS
verifies all endpoints so having no CA chain prevents TLS).

plugins/obs-outputs/librtmp/rtmp.c

@@ -344,7 +344,7 @@ RTMP_TLS_LoadCerts() {
 
     CFRelease(keychain_ref);
 #elif defined(__linux__)
-    if (mbedtls_x509_crt_parse_path(chain, "/etc/ssl/certs/") != 0) {
+    if (mbedtls_x509_crt_parse_path(chain, "/etc/ssl/certs/") < 0) {
         goto error;
     }
 #endif