test/spdkcli: Include errors from a failed command

Dump it to stdin to make the debugging easier.

Change-Id: I9b13d0a77e45aa84ec2a55b7b982225592f2566d
Signed-off-by: Michal Berger <michal.berger@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/17560
Reviewed-by: Konrad Sztyber <konrad.sztyber@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

test/spdkcli/spdkcli_job.py

@@ -14,7 +14,7 @@ def execute_command(cmd, element=None, element_exists=False):
     child.sendline(cmd)
     child.expect("/>")
     if "error response" in child.before.decode():
-        print("Error in cmd: %s" % cmd)
+        print("Error in cmd: %s (%s)" % (cmd, child.before.decode()))
         exit(1)
     ls_tree = cmd.split(" ")[0]
     if ls_tree and element: