Merge remote-tracking branch 'origin/pr/2498' into mbedtls-2.7

* origin/pr/2498:
  Adapt ChangeLog
  ssl_server2: Fail gracefully if no PEM-encoded CRTs are available
  ssl_server2: Skip CA setup if `ca_path` or `ca_file` argument "none"
  ssl_client2: Fail gracefully if no PEM-encoded CRTs are available
  ssl_client2: Skip CA setup if `ca_path` or `ca_file` argument "none"
diff --git a/ChangeLog b/ChangeLog
index f155a02..f376341 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -47,6 +47,9 @@
      Contributed by Peter Kolbus (Garmin).
    * Change wording in the `mbedtls_ssl_conf_max_frag_len()`'s documentation to
      improve clarity. Fixes #2258.
+   * Improve debug output of ssl_client2 and ssl_server2 in case suitable
+     test CRTs are available because MBEDTLS_PEM_PARSE_C is disabled.
+     Fixes #2254.
 
 = mbed TLS 2.7.10 branch released 2019-03-19