Revise energy scale (power) base test
Revise energy scale (power) base test

Update test_escale_base.robot to:
  - Resolve "Witherspoon phosphor-settings-manager:
    Input parameter for PowerCap is invalid.  Input: 500 Watts
    is not in range 556..3389".
  - Check and clear expected BMC error logs as a consequence
    of deliberately setting a power limit out of range.

Resolves openbmc/openbmc-test-automation#204
Change-Id: Iadb159d67c1b604aca675e59e2b94cc5bb80ff70
Signed-off-by: Steven Sombar <fb37bb6ac5c2258e1cbf80690dea88925949957e@us.ibm.com>

openbmc/openbmc-test-automation,openbmc/openbmc-test-automation