For patch sets on the ChangeScreen different commands for downloading
the patch sets are offered. For some installations not all commands are
needed. Allow Gerrit administrators to configure which download
commands should be offered.
Bug: issue 548
Change-Id: Ida3e00f3b98e37280ecded2e25b20fc0a21abec0
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>