Rephrase Changelog

Rephrase Changelog to be more coherent to users

ChangeLog

diff --git a/ChangeLog b/ChangeLog
index 48529f3..5945b7e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,8 +3,9 @@
 = mbed TLS x.x.x branch released xxxx-xx-xx
 
 Bugfix
-   * Fix handshake failure in NIST suite b, where the key was determined as
-     MBEDTLS_ECKEY instead of MBEDTLS_ECDSA.
+   * Fix mbedtls_x509_crt_profile_suiteb, which used to reject all certificates
+     with flag MBEDTLS_X509_BADCERT_BAD_PK even when the key type was correct.
+     In the context of SSL, this resulted in handshake failure.
 
 = mbed TLS 2.7.0 branch released 2018-02-03