squad.sh: use resilient calls for lavacli commands

Under heavy loads, lavacli commands may return 502 responses as the
log and link [1] below. To minimize possible non-200 responses from the TF LAVA
lab, call resilient_cmd function which tries the command a max number of times
until success.

    .
    .
    20:12:42 + echo 'Waiting for LAVA to complete'
    20:12:42 Waiting for LAVA to complete
    20:12:42 + lavacli jobs wait 74626
    20:18:52 Submitted.......................................................................
    20:20:19 Running................Unable to call 'jobs.wait': 502 Server Error: Proxy Error for url: https://****:****@tf.validation.linaro.org/RPC2
    20:20:19 ERROR: [flexible-publish] Execute Scripts (org.jenkinsci.plugins.postbuildscript.PostBuildScript@779e6243) failed
    .
    .
    20:20:19 Finished: FAILURE

[1]  https://ci.trustedfirmware.org/job/tf-a-builder/53668/console

Signed-off-by: Leonardo Sandoval <leonardo.sandoval@linaro.org>
Change-Id: I89b73b60e2bca477f60ee47470eab28543fb8c79
1 file changed