potential for black-holing log messages via transitive dependency on gulplog

`gulp-util.log` checks for `hasGulplog` on module initialization and if present, defers logging to `gulplog.info`, which in turn will eat any messages below `error` (I believe) unless there is explicitly an event handler for the other levels (info, warn, etc.).

This can happen 'accidentally' if a transitive dependency uses gulplog.

It _seems_ like the reasonable thing to do is to use `gulplog.error` to ensure all logging is output properly.