Removes the authorization header incase it exists
Removes the authorization header incase it exists

The authorization header if set to Bearer was causing S3 upload to fail
with the error "Unsupported authorization type".
The current setup of this example doesn't require authorization type.

Fixes danialfarid/angular-file-upload#382

nukulb/s3-angular-file-upload,adzample/s3-angular-file-upload,adzample/s3-angular-file-upload