jobs/coverity: remove display-name

Make it consistent with all other jobs and don't set a display name.
This way the job will be sorted properly in the list of jobs and won't
weirdly jump to the top when loading the page.

Change-Id: Idf1a8db45daf75ae110cfae3042627fbcdd14575

jobs/coverity.yml

@@ -9,7 +9,6 @@
     project-type: freestyle
     defaults: global
     description: 'Generated by job-builder'
-    display-name: 'Coverity-Upload'
     node: coverity
     builders:
       - shell: |