[FIXED JENKINS-11172] Don't throw exception on /signup when not possible
[FIXED JENKINS-25897] Add range check for H(X-Y) syntax
[JENKINS-25897] Add tests
[JENKINS-11172] Return HTTP 404 on /signup URL if not possible
Merge pull request #1500 from daniel-beck/JENKINS-25897

[FIXED JENKINS-25897] Add range check for H(X-Y) syntax
Noting #1500
[JENKINS-11172] Noting merge of #1388.