jobs/ttcn3: …-pablo-gtp: don't wipe workspace

The ttcn3-ggsn-test-kernel-* jobs should not wipe their workspace, so we
can avoid shallow-cloning the kernel if the commit did not change.

The way the scripts in docker-playground.git are written, this also
caused a permission error.

Change-Id: I4ac1b2c3f5ba63c131dd1d6a4888f32a27264eba
---
M jobs/ttcn3-testsuites.yml
1 file changed, 17 insertions(+), 0 deletions(-)

diff --git a/jobs/ttcn3-testsuites.yml b/jobs/ttcn3-testsuites.yml
index e212d93..35a893d 100644
--- a/jobs/ttcn3-testsuites.yml
+++ b/jobs/ttcn3-testsuites.yml
@@ -32,6 +32,8 @@
             Test osmo-ggsn master with the Debian kernel.
       - ttcn3-ggsn-test-kernel-pablo-gtp:
           timer: H 04 * * *
+          # Cache the linux source tree in the workspace of one node
+          wipe_workspace: false
           description: |
             Test osmo-ggsn master with the Linux kernel built from main of
             <a href="https://git.kernel.org/pub/scm/linux/kernel/git/pablo/gtp.git/">pablo/gtp.git</a>.

