Fix the flavor ram string value

Current test_create_flavor_using_string_ram specify " 1024 " as the
ram string value and the spaces are meaningless.
Current Nova API(v2.0) validation is loose and the API accepts this
value. However, new API(v2.1) will not allow this kind of value.
This patch removes these spaces from the test.

Change-Id: Ifaabcf04e2600bcec8043c981e320d47d8dc6379
Merge "Fix the flavor ram string value"