Clarify documentation of ssl_set_own_cert()

fixes #507
diff --git a/ChangeLog b/ChangeLog
index 3432118..20f7e5a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -18,6 +18,8 @@
      program programs/x509/cert_write. Fixes #1422.
    * Ignore iv in mbedtls_cipher_set_iv() when the cipher mode is MBEDTLS_MODE_ECB
      Fix for #1091 raised by ezdevelop
+   * Clarify documentation of mbedtls_ssl_set_own_cert() regarding the absence
+     of check for certificate/key matching. Reported by Attila Molnar, #507.
 
 Changes
    * Add tests for session resumption in DTLS.