Update libtracecmd to version 1.5.1 / rev 7 via SR 1142676
    
    https://build.opensuse.org/request/show/1142676
    by user dirkmueller + anag+factory
    - update to 1.5.1:
      * Fix free_zpage() offset accounting. The read_zpage() subtracted
        the offset from the file start to find where to get the
        compressed data, but the free_zpage() did not, and would fail to
        find and free the passed in zpage.
      * Have function_graph plugin break apart functions that migrate
        between CPUs from entry to exit even if there is no event in
        between.
      * Fix iterators for when there's CPUs with no data. It was using
        the total number of CPUs to iterate the cpu_data[] array, that
        only contains CPUs with content.
      * Fix iterator with respect to function_graph handle that may do
        a peek of the next event to know if it should merge the entry
        and exit events of a function.
      * Some other small fixes and clean ups
      * tracecmd_iterate_e