LAVA scripts: Don't assume job id is int

This no longer will be true with TuxSuite integration, so just treat id as
a string.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I37e3d0bfede394804dcc26fc71734cdf6ad16f58
diff --git a/tfm_ci_pylib/lava_rpc_connector.py b/tfm_ci_pylib/lava_rpc_connector.py
index da7989e..6baa90a 100644
--- a/tfm_ci_pylib/lava_rpc_connector.py
+++ b/tfm_ci_pylib/lava_rpc_connector.py
@@ -261,7 +261,7 @@
                     cur_status['error_reason'] = self.get_error_reason(job_id)
                     finished_jobs[job_id] = cur_status
                     _log.info(
-                        "Job %d finished in %ds with state: %s, health: %s. Remaining: %d",
+                        "Job %s finished in %ds with state: %s, health: %s. Remaining: %d",
                         job_id, time.time() - start_t,
                         cur_status['state'],
                         cur_status['health'],