Fixed missing references in load-subfile.js

load-subfile.js seemd to be broken in the latest version, gave me the following errors:
ReferenceError: path is not defined
    at /Users/simonihmig/Projects/bsp/node_modules/gulp-hub/lib/load-subfile.js:48:13
...
and
ReferenceError: tasks is not defined
    at /Users/simonihmig/Projects/bsp/node_modules/gulp-hub/lib/load-subfile.js:58:41

This should fix it!