title: Firebase hosting deploy error "HTTP Error: 404, Not Found"
body: <p>I don't know if this is related to the recent bump of firebase-tools to 6.0 or not. But I'm unable to deploy my files to a hosting project. </p>
  
  <p>The output after I type firebase deploy:</p>
  
  <pre>
  === Deploying to 'legofun-8f22d'...
  
  i  deploying hosting
  i  hosting[legofun-8f22d]: beginning deploy...
  i  hosting[legofun-8f22d]: found 42 files in /_site
  (node:10178) UnhandledPromiseRejectionWarning: Error
      at new FirebaseError (/usr/lib/node_modules/firebase-tools/lib/error.js:9:18)
      at Object.reject (/usr/lib/node_modules/firebase-tools/lib/utils.js:67:31)
      at /usr/lib/node_modules/firebase-tools/lib/deploy/hosting/prepare.js:48:26
      at arrayEach (/usr/lib/node_modules/firebase-tools/node_modules/lodash/lodash.js:516:11)
      at Function.forEach (/usr/lib/node_modules/firebase-tools/node_modules/lodash/lodash.js:9344:14)
      at module.exports (/usr/lib/node_modules/firebase-tools/lib/deploy/hosting/prepare.js:29:7)
      at _chain (/usr/lib/node_modules/firebase-tools/lib/deploy/index.js:22:40)
      at /usr/lib/node_modules/firebase-tools/lib/deploy/index.js:63:16
      at 
      at process._tickDomainCallback (internal/process/next_tick.js:229:7)
  (node:10178) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
  (node:10178) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
  ⠏  hosting: adding files to version [0/42] (0%)(node:10178) UnhandledPromiseRejectionWarning: Error
      at new FirebaseError (/usr/lib/node_modules/firebase-tools/lib/error.js:9:18)
      at module.exports (/usr/lib/node_modules/firebase-tools/lib/responseToError.js:38:12)
      at Request._callback (/usr/lib/node_modules/firebase-tools/lib/api.js:37:35)
      at Request.self.callback (/usr/lib/node_modules/firebase-tools/node_modules/request/request.js:185:22)
      at emitTwo (events.js:126:13)
      at Request.emit (events.js:214:7)
      at Request. (/usr/lib/node_modules/firebase-tools/node_modules/request/request.js:1161:10)
      at emitOne (events.js:116:13)
      at Request.emit (events.js:211:7)
      at IncomingMessage. (/usr/lib/node_modules/firebase-tools/node_modules/request/request.js:1083:12)
  (node:10178) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 6)
  
  Error: HTTP Error: 404, Not Found</pre>