network-legacy/ifup: drop redundant if-statement
    
    No need to check that `$ret` is 0, we're already running inside an
    if-statement block which checks this.
    
    (cherry picked from commit 7795fde44c54bfe753cc07999a4c2f9dd7e2820d)
    
    Resolves: #1807395
    
    patch_name: 0068.patch
    present_in_specfile: true
    location_in_specfile: 68
    squash_commits: true