Add newline when generating Dockerfile

Signed-off-by: Alessandro Di Federico <ale@rev.ng>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <1610080146-14968-36-git-send-email-tsimpson@quicinc.com>
Message-Id: <20210114165730.31607-5-alex.bennee@linaro.org>

tests/docker/docker.py

@@ -332,9 +332,9 @@ def build_image(self, tag, docker_dir, dockerfile,
                          (uname, uid, uname))
 
         tmp_df.write("\n")
-        tmp_df.write("LABEL com.qemu.dockerfile-checksum=%s" % (checksum))
+        tmp_df.write("LABEL com.qemu.dockerfile-checksum=%s\n" % (checksum))
         for f, c in extra_files_cksum:
-            tmp_df.write("LABEL com.qemu.%s-checksum=%s" % (f, c))
+            tmp_df.write("LABEL com.qemu.%s-checksum=%s\n" % (f, c))
 
         tmp_df.flush()