enable retries by using pipefail option in bash

By default shells don't stop on pipe errors (e.g. if the tedge http get command fails), so jq will always control the overall exit code as it is the last process in the pipe.

Using pipefail will ensure that the Execute Command will be retried if the http get command fails for some transient reason (e.g. service is restarting, or the network infrastructure has sporadic issues).

Signed-off-by: reubenmiller <reuben.d.miller@gmail.com>

Author: reubenmiller

tests/RobotFramework/tests/tedge/tedge_http.robot

@@ -47,8 +47,8 @@ Updating entities from a child device
 
 Accessing c8y from a child device
     ${external_id}=    Execute Command
-    ...    tedge http get /c8y/identity/externalIds/c8y_Serial/${PARENT_SN} | jq .externalId
-    Should Be Equal    ${external_id}    "${PARENT_SN}"\n
+    ...    bash -o pipefail -c "tedge http get /c8y/identity/externalIds/c8y_Serial/${PARENT_SN} | jq -r .externalId"
+    Should Be Equal    ${external_id}    ${PARENT_SN}\n
 
 Accessing file-transfer from a child device
     Execute Command    printf "source file content" >/tmp/source-file.txt