alpine-amd64-node10-tf-a: fix sshd startup

We need a custom setup-sshd script for Alpine, in order to generate SSH
host keys. The script should be run as root and we use the buildslave
user to login through SSH.

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
Change-Id: I09d2d7a4fdf3673ac37071c83d3a968ded3dbc8c
diff --git a/alpine-amd64-node10-tf-a/Dockerfile b/alpine-amd64-node10-tf-a/Dockerfile
index 2408dea..b51f62a 100644
--- a/alpine-amd64-node10-tf-a/Dockerfile
+++ b/alpine-amd64-node10-tf-a/Dockerfile
@@ -1,16 +1,18 @@
 FROM node:10-alpine
 
+# Can be overriden at build time
+ARG BUILDSLAVE_PASSWORD=buildslave
+
 COPY setup-sshd /usr/sbin/setup-sshd
 
 RUN set -e ;\
-    # install deps ;\
+    # install deps
     apk add openssh bash sudo ;\
-    # Setup buildslave user for Jenkins ;\
+    # Setup buildslave user for Jenkins
     adduser buildslave -D -s /bin/bash ;\
+    echo "buildslave:$BUILDSLAVE_PASSWORD" | chpasswd ;\
     echo 'buildslave ALL = NOPASSWD: ALL' > /etc/sudoers.d/jenkins ;\
     chmod 0440 /etc/sudoers.d/jenkins
 
-USER buildslave
-
 EXPOSE 22
 ENTRYPOINT ["/usr/sbin/setup-sshd"]