Give probe tests a second chance to pass

...and bump up their timeout, since that seems more likely to happen if
we have to retry.

Change-Id: Ie05521f6cd146234dc5615c96ad19681b43e9110

.zuul.yaml

@@ -244,7 +244,7 @@
     nodeset: centos-7
     description: |
       Setup a SAIO dev environment and run Swift's probe tests
-    timeout: 5400
+    timeout: 7200
     pre-run:
       - tools/playbooks/common/install_dependencies.yaml
       - tools/playbooks/saio_single_node_setup/setup_saio.yaml

tools/playbooks/probetests/run.yaml

@@ -21,6 +21,6 @@
       shell:
         cmd: |
           source ~/.bashrc
-          nosetests test/probe/
+          nosetests test/probe/ --with-id || nosetests --failed
         executable: /bin/bash
         chdir: '{{ zuul.project.src_dir }}'