Current behavior (1.7.5):

If the Jenkinsfile is deleted branch is still considered part of multiubranch project.

If all files including Jenkinsfile on branch is deleted then on next scan branch is removed from multibranch project.

Requested behavior:

If the Jenkinsfile is deleted then on next scan branch is removed from multibranch project.

Reproduction Steps:

1. Create multibranch project that scan //depot/project1/...
2. Add //depot/project1/main/Jenkinsfile and //depot/project1/main/f1.
3. Add //depot/project1/branch1/Jenkinsfile and //depot/project1/branch1/f1.
4. Click 'Scan Multibranch Pipeline Now'. Two branches are found.
5. 'p4 delete //depot/project1/branch1/Jenkinsfile' and submit.
6. Click 'Scan Multibranch Pipeline Now'.
7. Branch1 is not removed from project and build of Branch1 fails with

...Jenkinsfile not found
Finished: FAILURE