Removes memory allocation from free energy foreign lambda calcs.

Removes memory allocation from free energy foreign lambda calcs.

Removes the memory allocation from the free energy foreign
lambda calcs by declaring some new space in the enerd array, and
reinitializing only this space. Also makes the foreign lambda
calcs conditional on the group scheme and the non-bonded flag.

Change-Id: I98ed2f6ff45a4d33f9aa7dbde91364cf56c38eae