[snmp_facts.py]: do not query memory oid for eos switch

[lguohan]

eos switch does not support the two memory oids

Signed-off-by: Guohan Lu gulv@microsoft.com

Description of PR

Summary:
Fixes # (issue)

Type of change

• Bug fix
• [] Testbed and Framework(new/improvement)
• [] Test case(new/improvement)

Approach

How did you do it?

How did you verify/test it?

============================= test session starts ==============================
platform linux2 -- Python 2.7.12, pytest-4.6.9, py-1.8.1, pluggy-0.13.1 -- /usr/bin/python
  chedir: .pytest_cache
ansible: 2.8.7
rootdir: /data/tests, inifile: pytest.ini
plugins: ansible-2.2.2
collecting ... collected 1 item

test_nbr_health.py::test_neighbors_health FAILED                         [100%]

================================================== test session starts ==================================================
platform linux2 -- Python 2.7.12, pytest-4.6.9, py-1.8.1, pluggy-0.13.1 -- /usr/bin/python
cachedir: .pytest_cache
ansible: 2.8.7
rootdir: /data/tests, inifile: pytest.ini
plugins: ansible-2.2.2
collected 7 items                                                                                                       

snmp/test_snmp_cpu.py::test_snmp_cpu PASSED                                                                       [ 14%]
snmp/test_snmp_interfaces.py::test_snmp_interfaces PASSED                                                         [ 28%]
snmp/test_snmp_lldp.py::test_snmp_lldp PASSED                                                                     [ 42%]
snmp/test_snmp_pfc_counters.py::test_snmp_pfc_counters PASSED                                                     [ 57%]

Any platform specific information?

Supported testbed topology if it's a new test case?

Documentation