Include gerrit.war in api_{install,deploy}

This patch adds gerrit.war into api_{install,deploy} buck build step.
This allows third party maven based builds depend on gerrit.war
artifact.

Change-Id: I22c8d3339a1647913967e423e45462c2c5c255de
Signed-off-by: Dariusz Luksza <dariusz@luksza.org>