Removed unsed captcha file (#1567)

5 jobs from master in 7 minutes and 30 seconds (queued for 1 minute and 25 seconds)
Status Job ID Name Coverage
  Build
passed #9086
build_bionic

00:03:15

passed #9085
build_stretch

00:03:18

 
  Sign
passed #9087
sign

00:00:28

 
  Deploy
passed #9088
pages

00:00:28

failed pages:deploy

00:00:00