gerrit-verifications-dahdi: set concurrent: false

Each of the gerrit-dahdi-linux-* jobs has a 3-4 GiB workspace directory
with a full linux tree. We keep them on disk so we don't need to clone
the linux tree with each build.

This makes sense, but set concurrent to false to not create more of
these than necessary. These directories stood out when investigating
why build4 was running out of space.

Change-Id: I4fd4e85f0930b15b6c67e70fb2c140392c910bf5
---
M jobs/gerrit-verifications-dahdi.yml
1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/jobs/gerrit-verifications-dahdi.yml b/jobs/gerrit-verifications-dahdi.yml
index 5a8b3a6..2cf9e95 100644
--- a/jobs/gerrit-verifications-dahdi.yml
+++ b/jobs/gerrit-verifications-dahdi.yml
@@ -23,7 +23,12 @@
     name: 'gerrit-dahdi-linux-{type}-{linux-ver}'
     project-type: freestyle
     node: osmocom-gerrit
-    concurrent: true
+    # These jobs need an entire linux tree. We try to avoid cloning it more
+    # often than necessary, therefore we keep the workspace directory between
+    # job runs. Jenkins creates a new workspace for each concurrent job, which
+    # ends up consuming a lot of disk space so we disable it here. Besides disk
+    # space considerations, this job would run fine concurrently.
+    concurrent: false
     retry-count: 0 # scm checkout
     properties:
       - build-discarder:

