Changelog: Add an entry for Git Show header change

Change-Id: I6cdea03f2ebe372dfcd758f927a4adbcf3f96f60
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>
Squish: Explicitly set wanted kit

Change-Id: I287ce12a040a81a6392f39385c5a0c26d53b8e28
Reviewed-by: Robert Loehning <robert.loehning@digia.com>