ftplugin: Fix syntax for include/includexpr options
ftplugin: Fix syntax for include/includexpr options

In 1f90f5e59b2664e1e4f6a0abbd253d0f106101dd, these options were moved to
the ftplugin and changed from "let &l:" statements to "setlocal".
However, the right-hand side of the statement kept the let-style syntax.

derekwyatt/vim-scala