Fix Changelog, add separate test functions for hash of all-zero bits

Signed-off-by: TRodziewicz <tomasz.rodziewicz@mobica.com>
diff --git a/ChangeLog.d/issue1792.txt b/ChangeLog.d/issue1792.txt
index bd3d248..9949bf4 100644
--- a/ChangeLog.d/issue1792.txt
+++ b/ChangeLog.d/issue1792.txt
@@ -1,4 +1,3 @@
 Bugfix
    * Fix a bug in ECDSA that would cause it to fail when the hash is all-bits
-     zero.
-     Fixes #1792
+     zero. Fixes #1792