Bug in pot_+extrapolation='none' case fixed. I just removed the offending call
to "stop_exx", since in all other cases it seems that the calculation continues
with exact exchange on after the first scf step.


git-svn-id: http://qeforge.qe-forge.org/svn/q-e/trunk/espresso@11056 c92efa57-630b-4861-b058-cf58834340f0