use single ssh connection to onos
It belongs to VOL-4041 and is the second part.
Keyword 'Execute ONOS CLI Command on open connection' is deprecated
and is replaced by keyword
'Execute ONOS CLI Command use single connection' for all test suites
and libraries.

Change-Id: Ib5078b50d22e812e927e437a0e6f0e249f95ee9a
diff --git a/tests/functional/Voltha_ScaleFunctionalTests.robot b/tests/functional/Voltha_ScaleFunctionalTests.robot
index 3dd090a..58e6a8e 100755
--- a/tests/functional/Voltha_ScaleFunctionalTests.robot
+++ b/tests/functional/Voltha_ScaleFunctionalTests.robot
@@ -124,7 +124,7 @@
     FOR    ${I}    IN RANGE    0    ${num_olts}
         ${olt_serial_number}=    Set Variable    ${list_olts}[${I}][sn]
         ${of_id}=    Wait Until Keyword Succeeds    60s    5s    Validate OLT Device in ONOS    ${olt_serial_number}
-        Wait Until Keyword Succeeds  ${long_timeout}  20s  Validate DHCP Allocations  ${onos_ssh_connection}
+        Wait Until Keyword Succeeds  ${long_timeout}  20s  Validate DHCP Allocations  ${ONOS_SSH_IP}    ${ONOS_SSH_PORT}
         ...    16   ${of_id}    BBSM
     END
     #validate DHCP allocation for each port
@@ -185,7 +185,6 @@
 Setup Suite
     [Documentation]    Set up the test suite
     Common Test Suite Setup
-    ${onos_ssh_connection}    Open ONOS SSH Connection    ${ONOS_SSH_IP}    ${ONOS_SSH_PORT}
 
 Teardown Suite
     [Documentation]    Clean up devices if desired