BugFix! Phase factor for PW part of zmelt. make all OK!

Previous versions from 68b9a thru 7b2fe contained phase factor bugs.
(use shtv (gshtv is wrong and removed). 68b9a has an index bug (ig1
instead of ig2) at a Line 
   qg(1:3) = 2d0*pi * ( matmul(qbas, -ngvecp2(1:3,ig1)) )
in ppbafp.F.

This bug is seen for SiO2c example (Not for make gwall.)