delete files only from outDir (#2001)
delete files only from outDir (#2001)


zeit/next.js,flybayer/next.js,JeromeFitz/next.js,zeit/next.js,BlancheXu/test,nelak/next.js,azukaru/next.js,azukaru/next.js,JeromeFitz/next.js,azukaru/next.js,JeromeFitz/next.js,zeit/next.js,flybayer/next.js,azukaru/next.js,flybayer/next.js,JeromeFitz/next.js,BlancheXu/test,arunoda/next.js,kpdecker/next.js,flybayer/next.js,callumlocke/next.js,BlancheXu/test,giacomorebonato/next.js