tf-ci-gateway, tf-a-builder: Keep builds for 45 days.

Current figure of 14 days is just too little, there're broken links to
expired builds in *active* discussions. I wanted to make it 30 days,
but there're now suspicions that newer LAVA versions lead to some
regressions, and we again need to complete picture (older LAVA logs
*and* builds which started them) to investigate comfortably. So, make
it 45 days for now (based on current calculations, 60 days would
fit, but leave too little safety gap in case average build size
grows).

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Ie867a880dbaa92e2a59950b53d6b7c601ec85b02
diff --git a/tf-ci-gateway.yaml b/tf-ci-gateway.yaml
index 574f634..d082f00 100644
--- a/tf-ci-gateway.yaml
+++ b/tf-ci-gateway.yaml
@@ -9,7 +9,7 @@
       Main job entry point for a Trusted Firmware A (TF-A) CI.
     properties:
     - build-discarder:
-        days-to-keep: 14
+        days-to-keep: 45
     - throttle:
         option: project
         enabled: true