Change method name to test_get_volume_stats

Change test method name from test_update_volume_stats2 to
test_get_volume_stats in cinder/tests/test_eqlx.py.

It was pointed out by Change-Id:
I0642bdb911ca72517ed655f795e0055f4c4654b8

Change-Id: Id21c67e3e1151573e69ef21714fbf493f62ad425
Merge "Change method name to test_get_volume_stats"