jenkins test: clear singing-key-fingerpring from previous run
jenkins test: clear singing-key-fingerpring from previous run

f-droid/fdroidserver,f-droid/fdroid-server,f-droid/fdroid-server,f-droid/fdroidserver,f-droid/fdroid-server,f-droid/fdroidserver,fdroidtravis/fdroidserver,fdroidtravis/fdroidserver,f-droid/fdroidserver,fdroidtravis/fdroidserver,f-droid/fdroidserver,f-droid/fdroid-server,fdroidtravis/fdroidserver,f-droid/fdroid-server