don't try to delete job from server if first or last in suite
don't try to delete job from server if first or last in suite

This commit removes trying to delete job from server in case the
job is first or last in suite. As first and last job are not
reported to the server in the first place, we don't need to delete
them.

Signed-off-by: Shraddha Agrawal <01347c344ff9bfca8fb8f63951e1914d2ba7b87c@gmail.com>

SUSE/teuthology,ceph/teuthology,SUSE/teuthology,ktdreyer/teuthology,ceph/teuthology,ktdreyer/teuthology,SUSE/teuthology