fix obsolete method in vagrant layer
fix obsolete method in vagrant layer

Fixes warning:

    Compiling no file at Tue Nov  3 13:42:42 2015
    ../../init.el:Warning: `vagrant-tramp-enable' is an obsolete function; use
        `vagrant-tramp-add-method' instead.

tsonntag/dotemacs,tsonntag/dotemacs,tsonntag/dotemacs,tsonntag/dotemacs